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 ages

3.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 =



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.


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  • 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
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