Junyi has $4.25 in nickels and dimes. The number of dimes she has is ten less than twice the number of nickels. How many coins does she have?

Answer 1

d= 2n-10

425 = 10d + 5n

425 = 10(2n-10) +5n

425 = 20n -100 + 5n

425 = 25n -100

525 = 25n

n = 525/25 = 21 Nickels

d = 2n-10 = 42-10 = 32 Dimes

10(32) + 5(21) = 320+105= 425 = $4.25

total coins = 21+32 = 53 coins