Question Detail

The number of boys in a class is three times the number of girls. Which one of the following numbers cannot represent the total number of children in the class ?

Answer: Option C

Explanation:

Let number of girls = x and number of boys = 3x.

Then, 3x + x = 4x = total number of students.

Thus, to find exact value of x, the total number of students must be divisible by 4.

1. The number of boys in a class is three times the number of girls. Which one of the following numbers cannot represent the total number of children in the class ?

Answer: Option C

Explanation:

Let number of girls = x and number of boys = 3x.

Then, 3x + x = 4x = total number of students.

Thus, to find exact value of x, the total number of students must be divisible by 4.

2. First bunch of bananas has (1/4) again as many bananas as a second bunch. If the second bunch has 3 bananas less than the first bunch, then the number of bananas in the first bunch are

Answer: Option D

Explanation:

Let the number of bananas in the second bunch be x.
Then, the number of bananas in the first bunch
= x + 1/4 x
= 5/4 x
So,
5/4 x - x = 3
=> 5x - 4x = 12
x = 12

Number of bananas in first bunch
= 5/4 * 12 = 15

3. Find the least number which leaves a reminder of 3 when divided by 5, 6, 7 and 8, but leaves no reminder when divided by 9 ?

1683
1692
1598
1458

Answer: Option A

Explanation:

First of all, calculate LCM of 5, 6, 7 and 8 which is 840.
Suppose Number is K
then 840 * K + 3 is divisible by 9.
If K = 1, number = (840 × 1) + 3 = 843 which is not divisible by 9

If K = 2, number = (840 × 2) + 3 = 1683 which is divisible by 9

So 1683 is correct answer.

4. At the end of a business conference the ten people present all shake hands with each other once. How many handshakes will there be altogether ?

Answer: Option B

Explanation:

Total number of handshakes =
9+8+7+6+5+4+3+2+1 = 45

5. A group of 1200 persons consisting of captains and soldiers is travelling in a train. For every 15 soldiers there is one captain. The number of captains in the group is ?

Answer: Option B

Explanation:

Generally we may commit mistake of dividing 1200/15.
But out of 16 persons there is one captain.
so, it will be 1200/16 = 75