Question

One seventh of a herd of deer was seen in the forest. Thrice the square root of the herd had gone to mountains and remaining 21 deers were seen on the bank of a river. Find the total number of deer.
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Answer 1

Answer given in the attachment ✌

Answer 2

Given:

The deer present on the riverside is 21.

Thrice the square root of the number of deer had gone to the mountains.

One-seventh of the deer were in the forest.

To find:

The total number of deer.

Solution:

Let us take the total number of deer as X.

The number of deer in the forest = 1/7 of X = (1/7)X

The number of deer in the mountains = Thrice the square root of the number of deer

= 3$\sqrt{X}$

The number of deer on the riverside = 21

Total deer, X = Deer in forest + deer on mountain + deer on riverside

X = (1/7)X + 3$\sqrt{X}$+ 21            

X- (1/7)X - 3$\sqrt{X}$ -21 = 0             ( equation 1 )

Let us take $\sqrt{X}$ = y

Therefore, X = y²

Equation 1 becomes,

y²- (1/7)y² - 3y - 21 = 0

(6/7)y² - 3y - 21 = 0

6y² - 21y- 147 =0

2y²- 7y - 49 = 0 ( equation 2)

On solving the equation 2, we get,

y = 7, -7/2

Since y cannot be negative or fraction, we will take y = 7.

$\sqrt{X}$ = y = 7

∴ X = 49

Hence, the total number of deer is 49.