Question 118949
Let the no. of slinky sets purchased be x and no. of slippy sets purchased be y.

Then,3.5x+4.5y=41
and as total sets is 10, x+y=10

Multiplying eq 2 by 3.5 we get 3.5x+3.5y=35

thus, subtracting eq 2 from 1 we get,
y=6

thus no. of slippy sets is 6.