Question

Sandeep's father is 30 years older than him. The product of their ages from now will be 400. Present age of Sandeep is?
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Answer 1

Answer: 10 years

Step-by-step explanation:

Let Sandeep's age be x years & his father's age be y years.

According to 1st condition :-

y=x+30...........(1)

According to 2nd condition :-

x*y=400

x(x+30)=400.......from(1)

x^2+30x=400

x^2+30x-400=0

x^2+40x-10x-400=0

x(x+40)-10(x+40)=0

(x-10)(x+40)=0

x-10=0 or x+40=0

x=10 or x=-40

But age cannot be negative,

Therefore, x=10

Therefore the present age of Sandeep is 10 years.

Answer 2

Answer:

Given,

Sandeep's father is 30 years older than him. The product of their ages from now will be 400.

So, According to the question,

Let Sandeep's age be x years.

Then,

His father's age = x+30 years.

According to the question,

$= > x(x + 30) = 400 \\ = > {x}^{2} + 30x = 400 \\ = > {x}^{2} + 30x - 400 = 0 \\ = > {x}^{2} + 40x - 10x - 400 = 0 \\ = > x(x + 40) - 10(x + 40) = 0 \\ = > (x + 40)(x - 10) = 0$

So,

Either x=-40 or x=10

Since age can't be negative, so x=10.

Therefore, present age of sandeep is 10 years.