Quantitative Aptitude - Arithmetic Ability Questions

Let the speeds of two trains be 7X and 8X km/hr.

8x = 400/4

=> x= 12.5 km/hrX=4004=>X=12.5Km/hr

So speed of first train is 12.5*7 = 87.5 km/hr

Ans. 
4.5 = 7 x 0.5 + 1
5.5 = 4.5 x 1 + 1
12 = 5.5 x 2 + 1
49 = 12 x 4 + 1
? = 49 x 8 + 1, i.e. ? = 393

Let the average expenditure be Rs. x Then,

9x=[(8*30)+(x+20)]<=>9x =x+260 <=> x =32.50

Total money spent = 9x =  Rs. (9 x 32.5O) = Rs 292. 50

Note : If two trains (or bodies) start at the same time from points A and B towards each other and after crossing they take a and b sec in reaching B and A respectively, then: (A's speed) : (B's speed) = (b : a)

Therefore, Ratio of the speeds of two trains = 9:4 = 3 : 2

1 year = 365 days . A leap year has 366 days

A year has 52 weeks. Hence there will be 52 Sundays for sure.

52 weeks = 52 x 7 = 364days

366 – 364 = 2 days

In a leap year there will be 52 Sundays and 2 days will be left.

These 2 days can be:

1. Sunday, Monday

2. Monday, Tuesday

3. Tuesday, Wednesday

4. Wednesday, Thursday

5. Thursday, Friday

6. Friday, Saturday

7. Saturday, Sunday

Of these total 7 outcomes, the favourable outcomes are 2.

Hence the probability of getting 53 days = 2/7

The original fraction is  2551 × 350+100150+100  = 15/17.