Question
A team of 'x' boys can complete a
job in 18 days if they all work together. However, every day, 15 boys leave the team after starting the task, and it now takes 24 days to finish the work. Determine the value of '0.2x'.Solution
ATQ, Let the efficiency of each boy be 'b' units/day. Total work = x × 18 × b = '18xb' units ATQ: 18xb = x × b + (x - 15 × 1) × b + (x - 15 × 2) × b + (x - 15 × 3) × b + .... + (x - 15 × 23) × b Or, 18x = 24x - 15 × (1 + 2 + 3 + .... + 23) Or, 6x = 15 × (23/2) × (23 + 1) [since, sum of first 'n' natural numbers = (n/2) × (n + 1) ] So, 'x' = 690 Therefore, required value = 0.2 × 690 = 138
In January, 'A' earned Rs. 16,000 and spent 75% of it. The following month, his income rose by Rs. 4,000, and his savings went up by Rs. 2,000. Calculat...
A scored 46% marks and failed by 45 marks whereas B scored 76% marks, which was 75 more than the passing marks of the examination. Find the total marks ...
During a test, Rahul managed to get 38% and missed the cutoff by 16 marks, while Sneha got 45% and scored 5 marks above the passing marks. What was the ...
The population of a college grows by 25% annually. In 2019, the population was 24,000. By 2021, the ratio of boys to girls in the college is 7:8. What i...
A Company allow 8% commission on the total sales to its salesman but if the salesman is appointed on a fix salary of Rs. 10000 and 6% commission on the...
The price of a laptop undergoes two consecutive changes over two months. In the first month, its price decreases by 10%, followed by an increase of 20% ...
The monthly income of Raju was Rs. 13500 and his monthly expenditure was Rs. 9000. Next year his income increased by 17% and his expenditure increased b...
Monthly income of Eric and Olivia is Rs. 71,200 and Rs. 78,500 respectively. Eric spends 9%, 16%, and 18% on house rent, food, and education of children...
In a college, the ratio of male to female students is 5:3. If there were 10 additional males and 14 additional females, the ratio would change to 3:2. F...
The respective ratio of monthly income of A to monthly income of B is 10:11, and A’s saving is (100/13)% more than B’s saving. Find the expenditure ...
