Question
The mean of 15 values is 72. The mean of the first seven
values is 62, and the mean of the last five values is 86. The eighth value equals 25% of the ninth, and the tenth value is 75% more than the ninth. Determine the ninth value.Solution
Let ninth number is x Eighth number = 0.25x Tenth number = 1.75x According to question; x + 0.25x + 1.75x = 15 × 72 – 7 × 62 – 5 × 86 = 216 Or, 3x = 216 Or, x = 72
- ‘P’ and ‘Q’ together can finish a task in 15 days while ‘Q’ alone can do it in 25 days. If the ratio of efficiencies of ‘P’ and ‘R’ is ...
P and Q can complete a work in 26 days and 39 days, respectively. P, Q and R together can complete the work in 13 days. If R get a total wage of Rs. 585...
5 girls can do a piece of work in 9 days, 4 boys can do the same piece of work in 8 days, 6 men do the same piece of work in 2 days and 4 women can do t...
P and Q can individually complete a piece of work in 30 days and 45 days respectively. If R alone takes 1.5 times the time taken by P and Q together to ...
- 20 men working 6 hours a day can paint a building in 25 days. If 30 men work 8 hours a day, how many days will it take to paint the building?
'Ajeet' has an efficiency that is 40% lower than 'Chirag's, where as 'Bittu' is 20% more efficient than 'Chirag'. The time difference between 'Bittu' an...
‘X’ and ‘Y’ can do a task together in 15 days. If ‘X’ alone takes 25 days to complete it, then how much time will ‘Y’ take to finish the...
- Two workers, A and B, can finish a task in 36 days and 48 days respectively, working alone. How many days will they take to complete the work together?
12 men can finish a work in 20 days by working 6 hours a day. How many more men are needed to finish the work in 12 days by working 6 hours a day?
- If Neha can complete a work in 40 days by working 5 hours a day, how many hours per day should she work to complete the same work in 25 days?
