# 1. the sum of the ages of a man and his son is 45 years.5 years ago,the product of their ages was 4 times the man's age at that time.2.7 yrs ago varun's age was 5 times the square of swati's age.3 yrs hence her age will be two fifth of varun's age.find der ages3.the speed of a boat in still water is 8km/hr.it can go 15km upstream and 22km downstream in 5hrs.find da speed of the stream.4.a fast train takes 1 hour less than a slow train for a journey of 200km.if the speed of the slow train is 10km/hr less than that of the fast train.find the speed of the 2 trains. (pleez help. in the distance sums im not understanding which value will come 1st n which sine 2 put)

Dear Student!

Let the present age of Swati be x years.

7 years ago,

Varun's age = 5 × (Swati's age)2

∴ Varun's age = 5 × (x – 7)2

Present age of Varun = 5 (x – 7)2 + 7

3 years hence,

Swati's age =   Present age of Swati = 9 years

Present age of Varun = 3.

Let the speed of the stream be x km/hr.

Speed of the boat upstream = Speed of boat in still water – Speed of the stream

∴ Speed of the boat upstream = (8 – x) km/hr

Speed of the boat downstream = Speed of boat in still water + Speed of the stream

∴ Speed of the boat downstream = (8 + x) km/hr

Given, Time for upstream journey + Time for downstream journey = 5 hrs  Thus, speed of the stream is 3 km/hr.

We are happy to see the interest you are showing towards this section! Thank you for your response. I have already posted the answer to your two questions. However, due to a paucity of time we will not be able to immediately answer all your queries. Try to solve the remaining questions. If you have any problem in solving the questions, then get back to us we will be happy to help you.

Cheers!

• 22

1. let the son's age be x

dad's age = 45-x

we have,

(x-5) (40-x) = 4 (40-x)

or x-5 = 4 or x = 9

• 10

pleeez its urgent.i want the other 3 ans. too

• 6
What are you looking for?