The answer is 1,000! For each digit you get 10 options: 0,1,2,3,4,5,6,7,8,9.
So if you were to have ten options for each of the three digits you can enter, you multiply all possibilities together. So 10 times 10 is 100. 100 times ten is 1,000.
I think i know what you are trying to ask. the equation will be: 18+24x=75 You want to know how many t-shirts you can buy 18+24x=75 -18 -18 24x= 57 /24 /24 x=2.375 ~ 2 So he can only buy 2 t-shirts