Question

Stephanie has 23 coins in her piggy bank. She only puts dimes and pennies inside. If she has $1.58, how many dimes does she have?

Answer 1

Set this up as a system of equations where x = the number of dimes and y = the number of pennies

If she has a total of 23 coins then one equation is
\[x+y=23\]
And if the total is $1.58 the other equation is
\[10x + y = 158\]
subtract the two equations and solve for x
\[(10x - x) + (y - y) = (158-23)\]
\[9x = 135\]
\[x = 15\]
Thus, Stephanie has 15 dimes and 8 pennies.