Question

a child find 29 nickels and dimes. how many dimes are there if the total value of the coins are $2.10?

Answer 1

Devide 29 by 2.10 and you get 13.8095238 then round off to 13
So there are 13 dimes and 16 nickels
To check the answer just put 13 x 10 +16 x 5 in a calculator and the answer should be 210

Answer 2

X represents nickels
y represents dimes
x+y=29
5x+10y=210
multiply the first equation by -5 (elimination method)
-5x-5y=-145
then add the two equations together
5y=65
divide 5 from both sides
y=13
13 dimes