Lolo is 70 and his grandson is 10. In how many years will Lolo be exactly three times as old as his grandson?
Correct answer: A. 20 years
Solve 70 + x = 3(10 + x): 70 + x = 30 + 3x, so 40 = 2x and x = 20. Check: in 20 years Lolo will be 90 and the grandson 30.
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