Answer:
10 slices of pizza were sold
Explanation:
Let x be the no. of pizza slices sold
Let y be the no. of hot dogs
25 total items were sold
So, x+y=25 ---1
A pizza cost $2 and a hot dog costs $1
Cost of x slices of pizza = 2x
Cost of y hot dogs = y
They made total $35
2x+y=35 ---2
Substitute the value of y from 1 in 2
2x+25-x=35
x=35-25
x=10
Hence 10 slices of pizza were sold