Question
A, B, C, D, and E are five friends who went on a picnic.
Their average age is 43 years. The present age ratio of D to E is 4:5, and the present age ratio of A to B is also 4:5. Four years from now, the ratio of A's age to C's age six years from now will be 4:5. Additionally, four years from now, A’s age will be 10 years less than E's current age. What is the average age of D and E?Solution
Let the present age of A and B = 4x: 5x Four years from now the age of A and Six years from now the age of C = 4y : 5y Equate A in both cases 4x = 4y – 4 X = y – 1, y = x+1 Substitute the value of Y Age of C=5y – 6 => 5(x+1) – 6 = 5x+5-6=5x-1 So present ages of A, B and C = 4x : 5x : 5x – 1 Four years from now the age of A is 10 years less than E 4x +4 = E - 10 => E = 4x + 14 5 parts of E = 4x + 14 1 parts of E= 0.8x+2.8 4 parts of D = 3.2x + 11.2 So present ages of A, B, C, D and E = 4x : 5x : 5x – 1 : 3.2x+11.2 : 4x+14 Average age of all friends = 43 Total age of all friends = 43*5 = 215 years 4x + 5x + 5x – 1 + 3.2x+11.2 + 4x+14 = 215 21.2x = 190.8 X = 9 Substitute x value in D and E Average age of D and E =7.2 * 9 + 25.2 / 2 = 45 years.
A bag contains black and white balls, such that the probability of picking a black ball is 4/7. If the probability of picking two black balls without re...
A jar contains 6 pink, 2 black and 4 orange balls. If 3 balls are chosen at random without replacement, what is the probability that all 3 balls are of ...
A bag contains 3 black and 9 white balls. One ball is drawn at random. What is the probability that the ball drawn is white?
"A piggy bank comprises 5-rupee coins, 10-rupee coins, and 20-rupee coins. The quantity of 5-rupee coins in the piggy bank is 75% more than the number o...
- A jar contains six 50 paise coins, six Rs. 1 coins, and twelve Rs. 10 coins. One coin is lost. Find the probability that the lost coin is not a 50 paise co...
- Bag A contains 3 red, 4 black, 8 blue and 5 yellow balls. Bag B contains 5 red, 2 black, 4 blue and 3 yellow balls. Find the probability of drawing 2 blue ...
A box contains (x + 3) black balls, 6 yellow balls, and 5 orange balls. If two balls are selected at random and the probability of selecting two orange ...
Which of the following cannot be the probability of an event?
Find the probability that a number selected at random from first hundred number is a multiple of 3 or 5?
A game consists of tossing three coins once and then rolling two dice. Find the probability of getting exactly one tail in the coin toss and a sum equal...
