Three postal workers can sort a stack of mail in 15 minutes, 15 minutes, and 30 minutes, respectively. Find how long it takes them to sort the mail if all three work together. min

10 minutes

Step-by-step explanation:

x·1/20 + x·1/25 + x·1/100 = 1

Multiply each term by 100 to clear the equation of all fractions

100x/20 + 100x/25 + 100x/100 = 100

5x + 4x + 1x = 100

10x = 100

x = 10

The answer is 10 minutes

example 2 – simplify: step 1: completely factor both the numerators and denominators of all fractions. step 2: change the division sign to a multiplication sign and flip (or reciprocate) the fraction after the division sign; essential you need to multiply by the reciprocal. step 3 : cancel or reduce the fractions.