Answer :
there are 11 skateboards and 9 bikes.
Set up your equations: 4s+2b=52 and b+s=20
Multiply the 2nd by 2, 2b+2s=40
Subtract the second equation from the first
2s=22
so 11 skateboards and 9 bikes
Set up your equations: 4s+2b=52 and b+s=20
Multiply the 2nd by 2, 2b+2s=40
Subtract the second equation from the first
2s=22
so 11 skateboards and 9 bikes