You have the misfortune to own an unreliable clock.
This one gains exactly 15 minutes every hour.
It is now showing 3.00am and you know that is was correct at midnight, when you set it.
The clock stopped four hours ago, what is the correct time now?
[Ref: ZSIE] © Kevin Stone
Hint: How many clock-minutes pass for each real hour?
Since the clock is gaining 15 minutes every hour, for every real hour that has passed, the clock will show 75 minutes.
Since the clock shows 3.00am, we know that 180 clock minutes have passed.
This equals 144 real minutes (180 / 75 x 60), so the clock shows 2.24 am.
The clock stopped 240 minutes ago (4 hours), so the time must now be 6.24am. QED.
How many squares, of any size, can you find on this chess board that do not contain a Rook?
[Ref: ZDPX] © Kevin Stone
Hint: There are no squares of size 5x5.
There are 61 squares of size 1x1.
There are 39 squares of size 2x2.
There are 20 squares of size 3x3.
There are 5 squares of size 4x4.
A total of 61 + 39 + 20 + 5.
I started a journey to my Aunt's yesterday with a full tank of gasoline, 10 gallons, but at that exact moment my gasoline tank sprang a leak.
I managed to drive 50 miles, exactly one hour, before coming to a complete stop with an empty tank.
I know that the car manages 25 miles per gallon.
How quickly was I losing gasoline?
[Ref: ZRNJ] © Kevin Stone
Hint: How many gallons did the journey use?
Answer: 8 gallons an hour.
Since I was travelled 50 miles in the one hour, this must have used 2 gallons (at 25 miles per gallon).
So I must have lost the other 8 gallons through the hole.
What is the sum of all of the numbers from 1 to 1000?
Hint: Add the first number to the last - does this help?
It's easiest to see that the first and last number are 1 and 1000, which add to 1001.
The next two numbers we can add are 2 and 999, which add to 1001.
The next two numbers to add are 3 and 998, which add to 1001.
We can keep doing this 500 times, and in each case they add to 1001.
And 500 x 1001 = 500,500.
Using the BrainTracker grid below, how many words can you find? Each word must contain the central
G and no letter can be used twice. The letters do not have to be connected. Proper nouns are not allowed, however, plurals are. Can you find the nine letter word?
Excellent: 109 words. Good: 80 words. Average: 50 words.
[Ref: ZEDM] © Kevin Stone
Hint: Every word must contain the central letter.
aegis, age, agent, ague, anger, angriest, angst, argent, argue, auger, easing, eating, erasing, gain, gainer, gait, gaiter, gantries, garnet, gas, gate, gaunt, gear, genius, gent, genus, get, giant, girt, gist, gnat, gnu, grain, granite, grant, grate, gratis, great, grin, grist, grit, grunt, guest, guinea, guise, guitar, gun, gust, gut, ingest, nag, rag, rage, rang, range, rating, regain, reign, resign, resting, rig, ring, rug, ruing, rung, rusting, sag, sage, sang, searing, seating, sign, SIGNATURE, signer, signet, sing, singe, singer, snag, snug, stag, stage, stager, staring, sting, stinger, strange, string, strung, stung, sugar, suing, sung, surge, tag, tang, tangier, tearing, teasing, tiger, ting, tinge, tug, urge, urgent, usage, using.
aegis, ag, age, ageist, agent, agents, ager, agers, ages, agin, agist, ague, agues, aigret, aigrets, anger, angers, angriest, angst, argent, argents, argue, argues, argus, astringe, auger, augers, augite, augites, earing, earings, easing, easting, eating, eatings, egis, eng, engirt, engs, erasing, erg, ergs, gae, gaen, gaes, gain, gainer, gainers, gains, gainst, gait, gaiter, gaiters, gaits, gan, gane, ganister, gantries, gar, garnet, garnets, garni, gars, gas, gast, gaster, gastrin, gat, gate, gates, gats, gaun, gaunt, gaunter, GAUNTRIES, gaur, gaurs, gear, gears, gen, genius, gens, gent, gents, genu, genua, genus, gest, get, geta, getas, gets, giant, giants, gie, gien, gies, girn, girns, girt, girts, gist, gnar, gnars, gnat, gnats, gnu, gnus, grain, grains, gran, granite, granites, grans, grant, grants, grat, grate, grates, gratin, gratine, gratins, gratis, great, greats, grin, grins, grist, grit, grits, grue, grues, grunt, grunts, guan, guans, guar, guars, guest, guinea, guineas, guise, guitar, guitars, gun, gunite, gunites, guns, gurnet, gurnets, gust, gustier, gut, guts, gutsier, ingate, ingates, ingest, ingesta, ingrate, ingrates, nag, nags, negus, rag, rage, rages, ragi, ragis, rags, rang, range, ranges, rangiest, rasing, rating, ratings, reagin, reagins, reg, regain, regains, regina, reginas, regius, regna, regs, reign, reigns, renig, renigs, resign, resting, retag, retags, reusing, rig, rigs, ring, rings, rug, ruga, rugae, rugate, rugs, ruing, rung, rungs, rusting, sag, sage, sager, sagier, sang, sanger, sarge, sating, sauger, sauteing, seagirt, searing, seating, seg, segni, sengi, sering, seringa, sign, SIGNATURE, signer, signet, sing, singe, singer, snag, snug, stag, stage, stager, stagier, staig, stang, staring, sting, stinger, strang, strange, string, strung, stung, sugar, suing, sung, surge, tag, tags, tang, tangier, tangs, targe, targes, taring, tearing, teasing, teg, tegs, tegua, teguas, terga, tiger, tigers, ting, tinge, tinges, tings, tragi, tragus, triage, triages, trig, trigs, trueing, trug, trugs, truing, tug, tugs, tung, tungs, ungirt, unitage, unitages, unrig, unrigs, urge, urgent, urges, usage, using.