Thursday 13 October 2011

DAY 369

Every resident of Sponge City owns one, and only one, car. Every license plate is different and consists of one letter (A - Z) and one single-digit number (0 - 9). Either the letter or the number can come first. If every possible combination is used, how many people live in Sponge City?

Answer:

520 ........... 26 X 10 = 260 / 260 X 2 = 520 (since the letter and number can come in either order)


Wednesday 12 October 2011

DAY 368

John and Mary each have a number of widgets. Mary said to John, "If you give me one widget, I'll have twice as many as you, but if I give you one widget, we'll each have the same number." How many widgets did each one have?

Answer:

Mary had 7 and John had 5 ....... If giving one widget to John will make their numbers equal, Mary must have two more widgets than John. If x = the number of John's widgets, then x + 2 = the number of Mary's widgets ........... (x + 2) + 1 = 2(x - 1)

Tuesday 4 October 2011

DAY 367

Bill filled the tank of his car with 12 gallons of gas. The tank immediately sprang a leak. Bill drove at 50 miles per hour and ran out of gas 4 hours later. His car gets 25 miles per gallon.
How much gas did Bill lose?

Answer:

4 gallons ....... 50 mph for 4 hours = 200 miles.
At 25m/gal. = 8 gallons. 12 - 8 = 4
DAY 366

Two in a whole and four in a pair,
And six in a trio you see;
And eight's a quartet,
But what you must guess
Is the name that fits just one of me.

Answer:

one-half