What is the least number which, when increased by 7, becomes exactly divisible by 18, 24 and 30?

353Correct answerYour answer360Correct answerYour answer367Correct answerYour answer713Correct answerYour answer

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CorrectNot quiteAnswer A

Correct answer: A

Number + 7 must be a common multiple; the least is $\operatorname{LCM}(18, 24, 30) = 360$ .
Number = $360 - 7 = 353$ .

Worth noting

367 adds 7 instead of subtracting; 713 uses the second common multiple, 720.

Ten questions from HCF & LCM, at your own pace.

Explanation