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Question

Twin​ brothers, Billy and​ Bobby, can mow their​ grandparent's lawn together in 100 minutes. Billy could mow the lawn by himself in 35 minutes less time than it would take Bobby. How long would it take Bobby to mow the lawn by​ himself?

Answer 1

x represents the time Bobby needs

x - 35 represents the time Billy needs

(x / 100) + (x - 35 / 100) = 1

Can you solve for x and answer?