Maths Questions

# SSC CPO Maths Questions: 5th April 2020

**Q1. Two trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other is:**

**(A) 9 (B) 9.6 (C) 10 (D) 10.8**

**Ans.- (D) Solution :- Let S**

_{1 }= 60 km/hr, S_{2 }= 40 km/hr**D**

_{1}= 140 m = 0.14 km, D_{2 }= 160 m = 0.16 km**Time = (D**

_{1 }+ D_{2})/ (S_{1}+ S_{2}) = (0.14 + 0.16)/ (60 + 40)**Time = 0.3/100 hr = (0.3/100) * 3600**

**=> Time = 10.8**

**Q2. A train speeds past a pole in 15 seconds and a plateform 100 m long in 25 seconds. Its**

**Length is:**

**(A) 50 m (B) 150 m (C) 200 m (D) Data inadequate**

**Ans.- (B) Solution :- Let length of train = x**

**Speed of train is = x/15**

**Length = Speed * Time**

**=> 100 + x = (x/15) * 25**

**=> x = 150 meters.**

**Q3. A train 110 meters long is running with a speed 60 kmph. In what time will it pass a man?**

**Who is running at 6 kmph in the direction opposite to that in which the train is going?**

**(A) 5 sec (B) 6 sec (C) 7 sec (D) 10 sec**

**Ans. - (B) Solution: - Let S**

_{1}= 6 kmph, S_{2}= 60 kmph**Avg. speed = 60 + 6 = 66 kmph = 66*5/18 = 55/3 m/sec**

**L**

_{2}= 110 meters**T = 110 / (55/3) = 6 sec.**

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