Question

A person has 17 coins, all nickels and dimes, worth $1.25. How many nickels are there?
a)10
b)8
c)9

Answer 1

This is a problem of guess and check; there's no easier way to do it.

Answer 2

But in this case you must have an odd number of nickels to make the 5 cents, so your answer is 9 nickels.

Answer 3

you can check this by multiplying each one by .05:
9*.05=.45
the rest of the coins left, are 8 of them, and their dimes.
.10*8=.80
.80+.45= 1.25

Answer 4

so C) is the correct response