Question Detail

587 * 999 = ?

586411
586413
486411
486413

Answer: Option B

Explanation:

Trick: 587 * (1000 - 1) = 587000 - 587 = 586413

1. 6897 is divisible by

11 only
19 only
both 11 and 19
neither 11 nor 19

Answer: Option C

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. 7589 - X = 3434

4155
2321
3155
None of above

Answer: Option A

4. 1307 * 1307 = ?

1608249
1508249
1408249
1708249

Answer: Option D

Explanation:

\begin{aligned}
(a + b)^{2} = (a^2 + b^2 + 2ab)
\end{aligned}
\begin{aligned}
1307^{2} = (1300 + 7)^2 = (1690000 + 49 + 18200)
\end{aligned}

5. 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.