Mariko has 30 nickels and dimes. she has 12 more nickels than dimes. how many dimes does mariko have?

Me with this one question, and i'll upvote the brainliest answer

At the beginning of year 1, carlos invests $600 at an annual compound interest rate of 4%. he makes no deposits to or withdrawals from the account. which explicit formula can be used to find the account's balance at the beginning of year 5? what is, the balance?

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.