Question Detail

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

1. What least number must be subtracted from 427398 so that remaining number is divisible by 15

Answer: Option A

Explanation:

On dividing 427398 by 15 we get the remainder 3, so 3 should be subtracted

2. 217 * 217 + 183 * 183

70578
82578
80578
80568

Answer: Option C

Explanation:

\begin{aligned}
\frac {1}{2}\times 2(a^2 + b^2) = \frac {1}{2} \times [(a + b)^2 + (a - b)^2]
\end{aligned}
\begin{aligned}
= \frac {1}{2} \times [(217 + 183)^2 + (217 - 183)^2] = 80578
\end{aligned}

3. What least value should be replaced by * in 223*431 so the number become divisible by 9

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.

4. What least number should be added to 1056, so that the sum is completely divisible by 23

Answer: Option C

Explanation:

(1056 / 23) gives remainder 21

21 + 2 = 23, So we need to add 2

5. \begin{aligned}
46^2 - (?)^2 = 4398 - 3066
\end{aligned}

Answer: Option D

Question Detail

Simplify 586645 * 9999

1. What least number must be subtracted from 427398 so that remaining number is divisible by 15

2. 217 * 217 + 183 * 183

3. What least value should be replaced by * in 223*431 so the number become divisible by 9

4. What least number should be added to 1056, so that the sum is completely divisible by 23

5. \begin{aligned} 46^2 - (?)^2 = 4398 - 3066 \end{aligned}

5. \begin{aligned}
46^2 - (?)^2 = 4398 - 3066
\end{aligned}