Find the number in each case
a) 15% of a number is 3
b) 160% of a number is 80
what are the number in both a and b?

It seems like you have the answer already. but heres how its calculated.
 
so the missing number is 20 **cross multiply 100 and 3 to get 300 then divide 15 into 300 to get 20**

 
so the missing number is 50
 **cross multiply 100 and 80 to get 8000 then divide 160 into 8000 to get 50**

 

If there are four friends then each would get, 1.25 or 1 1/4. so this is how i solved 5 ÷ 4 = 1.25 . hope this ; )