Quantitative Aptitude - Arithmetic Ability Questions

(4a+7b)(4c-7d) = (4a-7b)(4c+7d)

(4a+7b)/(4a-7b) = (4c+7d)/(4c-7d)

Using componendo and dividendo

(4a+7b)+(4a-7b) / (4a+7b)-(4a-7b)

= (4c+7d)+(4c-7d) / (4c+7d)-(4c-7d)

Or 8a/14b = 8c/14d

Or a/b = c/d

Time required will be in ratio = 5:4

B alone will do it in =16 days

Given Loss = Rs. 40.4
We know loss = cost price - selling price
40.4 = CP - 35(15)
=> CP = 40.4 + 525
=> CP = Rs. 565.4
Now the New selling price of waffer is Rs. 18
=> SP = 35(18) = 630
Now Gain = SP - CP = 630 -565.4 = Rs. 64.6.

Girl eats 112 chocolates in 30 sec

so she can eat in 12 sec is 12 x 112/30 = 44.8 chocolates.

Her boy friend can eat one-half of 112 in twice of 30 sec

so he can eat 56 in 60 sec

Then he can eat in 12 sec is 56 x 12/60 = 11.2 chocolates.

Hence, together they can eat = 44.8 + 11.2 =56 chocolates in 12 seconds.

Total Water reqduired = 5000 × 150 lit = 750,000 litres = 750 cu.m.

Volume of tank = 20 × 15 × 5 = 1500 Cu.m.

Number of days required =1500/750 = 2 days.

$$\begin{gathered} 3 \\ 32 + 3 = 12 \\ 5 \\ 52 + 5 = 30 \end{gathered}$$