The sum of ages of mother and son is 47 years. Before 10 years, the product of their ages is 50. The difference between the ages of mother and a son is –

Ratio of speed of boat in down stream and speed of stream is 9:1, if speed of current is 3 km per  hr, then find distance travelled(in km) upstream in 5 hours.

In what ratio should wheat of ₹ 14-40 per kg be mixed with wheat of ₹ 11-40 per kg so that the price of the mixture becomes ₹ 12-60 per kg

The average of 30 numbers is 40 and that of the other 40 numbers is 30. The average of all the numbers is-

A and B together can do a piece of work in 12 days, A and C together can do the same work in 15 days. If B and C together can do the same work in 20 days, then in how many days A, B and C together can complete the same work?

Find the next term in the series.1329, 997, 725, 507, 337, ?

Find the greatest value of k for which the 6-digit number 24312k is divisible by 6.

AC is a chord of circle whose centre is at O. If B is any point on the arc AC and ∠OCA=20⁰ , then the magnitude of ∠ABC is