# TCS Papers: Sample Questions 121 - 123 of 502

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## Question number: 121

### Write in Short

What is the unit of ?

### Explanation

• SI unit of momentum:
• SI unit of velocity:
• SI unit of force:
• SI unit of time: s
• We are asked to find the SI unit of
• Computing this, meter/second will remain.
• is the SI unit of velocity.

## Question number: 122

MCQ▾

### Question

The current of a stream runs at 1km/hr. A motor boat goes 35 km upstream and back again to the starting point in 12 hours. What will be the speed of motor boat in still water?

### Choices

Choice (4) Response

a.

8.5 km/hr

b.

7 km/hr

c.

8 km/hr

d.

6 km/hr

d.

### Explanation

• Speed of stream = 1km/hr
• Motor boat goes 35 km upstream and downstream in 12 hours.
• Let the speed of motor boat be x km/hr

So,

• So, possible value of motor boat’s speed can be 6 km/hr.

## Question number: 123

### Write in Short

The ages of two friends is in the ratio 6: 5. The sum of their ages is 66. After how many years will the ages be in the ratio 8: 7?

### Explanation

• Ratio of ages of two friends is 6: 5
• Let their ages be 6x and 5x.
• Sum of their ages is 66, i. e.

• Their ages will be, and respectively.
• We are asked to find after how many years ratio of their ages will be 8: 7
• We can write,

• So, after 12 years ratio of their ages will be .