Fresh grapes contains 80 percent water while dry grapes contains 10 percent water. If the weight of dry grapes is 250kg. What was its total weight when it was fresh?
Answer: B In 250kg there is 225 kg pulp and 25 kg liquid. Now, 225 = 20%(Because 80% water is contained in grapes) Total weight of fresh grapes = 225*5 = 1125.
Q. No. 20:
A mixture(40 L) contains conic and water in the ratio 3:1. To make the ratio 5:2, how much additional amount of water is required?
Answer: D In 40:- conic = 30 and water =10 Now, 30/(10+x) = 5/2 On solving we get, x= 2L
Q. No. 21:
The ratio of A's age to B's age is the same as the ratio of the ages of their respective elder sisters. The ratio of the difference of the ages of A's and B's to that of the difference of the ages of their respective elder sisters is 1:2. What is the ratio of the sum of the ages of their respective sisters to the sum of the ages of A and B?
Answer: A Let A's age =x, and A's sister age = p B's age =y and B's sister age =q x/y = p/q Using Componendo and dividendo (x+y)/(x-y) = (p+q)/(p-q) =1/2 Thus, (p+q)/(x+y) = 2
Q. No. 22:
A certain number is added to each of a pair of numbers which are in the ratio 4:7. The sum of the resulting numbers is 75 and their ratio (taken in the same order as mentioned above) is 8:17. What is the number added?
Answer: A Ratio of numbers =8:17 Sum of the resulting numbers =75 Hence, the numbers obtained after addition are 8/25 * 75 = 24 and 17/25 *75 =51 i.e 4K+L =24 and 7K+L=51 On solving these equation we get L= -12.
Q. No. 23:
A precious stone worth Rs 10872 fell and broke into three pieces, the weights of which are proportional to 1:2:3. The value of each stone is directly proportional to the square of its weight. Find the loss in the value caused by the breakage?
Answer: C Let the initial weights of the stone (before breaking) be 6w. Weights of the broken stones are w, 2w and 3w respectively. Initial value of the stones (in Rs) = 10,872 10872 = 36 k*w2 Total value of the pieces of the stone = (12+22+32)w2*k = 14k*w2 Loss in value = 22 w2k => 22* 10872/36 = 22*302 = 6644
Q. No. 24:
The concentration of an acid solution is inversely proportional to the volume of the solution if the amount of acid is not changed. A 40% hydrochloric acid solution becomes 30% solution when 30L of water is added to it. Find the original volume of the solution.
Answer: B The original concentration = 40% The final concentration = 30% Ic * Iv = Fc * Fv where, Ic, Fc indicates initial and final concentration respectively. Iv and Fv indicates initial and final volume respectively. 30/40 = Iv/Fv => Fv = 4/3 *Iv There is an increase of 1/3* Iv , which is 30L. Hence, initial volume = 30*3 = 90L