One-fourth of a herd of cows is in the forest. Twice the square root of the herd has gone to mountains and he remaining 15 are on the banks of a river. The total number of cows is:
A
6
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
100
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
63
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
36
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution
The correct option is D36 Let the total number of cows be x. Hence x4+2√x+15=x 3x4−15=2√x 3x−60=8√x Let √x=y ∴3y2−8y−60=0 y=6 and y=−103 ∴√x=6 x=36