Sunday, 13 March 2016

Quant Quiz for Railway, UKPSC FRO and SSC CGL

1.The average speed of a tractor is two–fifths the average speed of a car. The car covers 450 km in 6 hours. How much distance will the tractor cover in 8 hours?
(1) 210km
(2) 240 km
(3) 420km
(4) 480 km
2.The simple interest accrued in 3 years on a principal of Rs 25,000 is three–twentieths the principal. What is the rate of simple interest pcpa?
(1) 5
(2) 4
(3) 6
(4) 3
3. A boat travels 24 km upstream in 6 hours and 20 km downstream in 4 hours. Then the speed of boat in still water and the speed of current are respectively?
(1) 4 kmph and 3 kmph
(2) 4.5 kmph and 0.5 kmph
(3) 4 kmph and 2 kmph
(4) 5 kmph and 2 kmph
4.The product of the LCM and HCF of two numbers is 24. The difference of the two numbers is 2. Find the numbers?
(1) 8 and 6
(2) 8 and 10
(3) 2 and 4
(4) 6 and 4
5.Population of a village decreases annually by 20%. If its population 2 years ago was 10, 000. What will be its present population?
(1) 6,000  
(2) 8,000  
(3) 6,400
(4) 7, 600

Solutions :

1. (2); Average speed of the car = 450/6 = 75 km/h
Average speed of the tractor = 75 ×2/5 = 30 km/h
Distance covered by the tractor in 8 hr = 30 × 8 = 240 km

2. (1); S.I=(3/20)P;
Using formula SI=(P*R*T)/100;
where SI=simple interest , R=rate ,T=time, P= Principal
            (3/20)P=P*3*R/100;
            R=5%
3. (2)The speed downstream  = 20/4 = 5 km/hr
         The speed upstream     = 24/6 = 4 km/hr
        The speed of boat in still water = (5+4)/2 = 4.5 km/hr
                The speed of current = (5-4)/2 = 0.5 km/hr
so , The speed of boat and current are 4.5 km/hr and 0.5 km/hr
NOTE : If the speed downstream is a km/hr and the speed upstream is b km/hr, then:
Speed in still water =(a + b)/2 km/hr.
Rate of stream(or current)  =(a - b)/2 km/hr.

4. (4); Let 1st number = x, second number = x+2
using formula=> 1st no. * 2nd no.= L.C.M*H.C.F
x*(x+2)=24
x=4 and x=6

5. (3) Population two years ago = 10,000, as population is decreases annually by 20% ,so its becomes 80%(100%-20%)of previous year.
      Present population = 80% of 80% of 10,000 = 6400




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