Answer:
See explanation
Step-by-step explanation:
Step 1. Substitute for d to solve for n:
From the first equation:
[tex]d=70-n[/tex]
Then substitute it into the second equation:
[tex]0.1(70-n)+0.05n=5.5\\ \\7-0.1n+0.05n=5.5\\ \\7+(-0.05n)=5.5\\ \\-0.05n=5.5-7=-1.5\\ \\n=\dfrac{-1.5}{-0.05}=30[/tex]
Step 2: Substitute for n to solve for d:
[tex]d+n=70\\ \\d+30=70\\ \\d=70-30=40[/tex]
There are 40 dimes and 30 nikels in the piggy bank
