Iknow the 90 percent number so how do i find the 100 perent number

It takes evan 6 3/4 to mow 3 lawns. it takes 2 1/3 hours to mow me. gals lawn and 1 3/4 hot mow ms. lee’s lawn. how many hours does it take evan to mow the third lawn?

21 a stick 7 inches long is broken into two pieces, so that one piece is twice as long as the other one. how long are the two pieces?

The salesperson earns a 5% commission on the first $5,000 she has in sales. the salesperson earns a 7.5% commission on the amount of her sales that are greater than $5,000. this month the sales person had $8,000 in sales. what amount of commission, in dollars, did she earn?