Question
A number when divided by 21 gives a remainder of 15.
What will be the remainder when twice that number is divided by 21?Solution
ATQ,
Number = (21A + 15), where 'A' is a constant.
Therefore, required remainder = [2 Γ (21A + 15)] Γ· 21
= (42A + 30) Γ· 21
= (42A + 21 + 9) Γ· 21 = 9
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