The greatest number by which the product of three consecutive multiples of 3 is always
54
81
162
243
Answer: Option C
Explanation:
3*6*9 = 162
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Similar Questions :
1. What least value should be replaced by * in 223*431 so the number become divisible by 9
3
4
5
6
Answer: Option A
Explanation:
Trick: Number is divisible by 9, if sum of all digits is divisible by 9, so (2+2+3+*+4+3+1) = 15+* should be divisible by 9,
15+3 will be divisible by 9,
so that least number is 3.
2. 1939392 * 625
1212120010
1212120000
1212120011
1212121010
Answer: Option B
Explanation:
Trick: when multiplying with \begin{aligned} 5^n
\end{aligned} then put n zeros to the right of multiplicand and divide the number with \begin{aligned} 2^n
\end{aligned}
So using this we can solve this question in much less
time.
\begin{aligned} 1939392 \times 5^4 = \frac {19393920000}{16} = 1212120000
\end{aligned}
3. Simplify 586645 * 9999
5865863355
5665863355
4865863355
4665863355
Answer: Option A
Explanation:
Although it is a simple question, but the trick is to save time in solving this.
Rather than multiplying it we can do as follows:
586645 * (10000 - 1) = 5866450000 - 586645 = 5865863355