Alison has $1.60 worth of nickels and dimes in her coin purse. she has 11 more nickels than dimes. how many of each coin does she have?

A nickel = 5 cents = $0.05
A dime = 10 cents = $0.10

Let the number of nickels be x and the number of dimes be y, then
0.05x + 0.1y = 1.6
5x + 10y = 160 . . . (1)
x = y + 11 . . . (2)

Putting (2) into (1) gives\
5(y + 11) + 10y = 160
5y + 55 + 10y = 160
15y = 160 - 55 = 105
y = 105/15 = 7
x = 7 + 11 = 18

Therefore, He has 18 nickels and 7 dimes.