Question

If Johnny can solve 90% of the problems, then what is the complement?

Answer 1

Answer:

Let the number of problems be x

Number of problems Johnny can solve is 90% of x that is 9×x÷10

To get the complement of it we need to subtract the given value from 90

Let the complement be y

y+9x÷10=90

y= 90- 9x÷10

Let the percentage be some n

n×x÷100= 90- 9x÷10

nx =( 900-9x)×10

n =   9000-90x

If the number of problem is 100 complement is 10%