Quantitative Aptitude - Arithmetic Ability Questions

If t1 and t2 are the upstream and down stream times. Then time taken in still water is given by 

2×t1×t2t1+t2=2×12×2436=16h

Let the Journey on foot be x km

Journey on cycle = (80 – x) km

∴x8+80-x16= 7 

=> x = 32km

Therefore,  Distance covered on foot in 4 hrs = ( 4 x 8) = 32 km

 H   L   C   N    T    A   U   I   O

      L        N          A        I

There are total 131 letters out of which 7 are consonants and 6 are vowels. Also ther are 2L's , 2N's, 2A's and 2I's.

If all the consonants  are together then the numberof arrangements = 7!2!x 1/2! .

But the 7 consonants  can be arranged themselves in  7!2! x 1/2! ways. 

Hence the required number of ways = 7!2!2!2 = 1587600

Let the total population be 'P'

P x (96/100) = 23040

P = 240 * 100

P = 24000.

Given 40% minimum passing marks for boys = 483 + 117 = 600
=> 1% = 600/40
=> 100% = 600 x 100/40 = 1500
Minimum passing marks for girls = 35% of 1500 = 35 x 1500/100 = 525.

150 men in 25 days do = 14 work  

Let 1 man in 1 day does = x  work  

Total work done by 150 men in 25 days = 150x *  25 = 14   work => x = 115000   

Therefore, 100 men in 60 days do = 100 * 60x = 6000x work = 6/15 = 2/5

Total work done =14 + 25 = 1320 

Therefore, Remaining work = 1 - 1320 = 720  

Remaining time = 130 - (25+60+10) = 35 days 

Therefore, work is done in 25 days by 150 men.

Therefore, Work is done in 35 days by 150 men.

Hence, he should employ 50 more men.

Let the required fraction be x. Then, (1 / x )- x = 9/20
1 - x^(2) / x = 9 / 20  =>  20 - 20 * x^(2) = 9 * x.
20 * x^(2) + 9 *x - 20 = 0.
=> (4 * x + 5) (5 * x - 4) = 0.
=> x = 4 / 5.

In 12 hours, they are at right angles 22 times.
In 24 hours, they are at right angles 44 times.