A stack of pennies and dimes has a total value of $2.31. How many dimes are in the stack if there are twice as many dimes as pennies

Question

Math problem

Answer 1

d = 2p, because the total number of dimes is twice pennies.

 

p + 10d = 231, because a penny is 1 cent, but we don't write 1p

 

Since d = 2p, we can substitute.

 

p + 10(2p) = 231

p + 20p = 231

21p = 231

p = 11

 

Since d = 2p, d = 2(11) = 22

 

Hope this helps!