Question

3.
There are two buildings P and Q. If
15 persons are sent from P to Q. then the
number of per sons in each building is
the same. If 20 persons are sent from a
to P, then the number of persons in P
is double the number of persons in Q.
How many persons are there in
building P?
(a) 80
(b) 140
(c) 120
d)90​

Answer 1

Answer:

C

Step-by-step explanation:

Answer : C

Discuss it below :

Let the number of persons in building P = p

and the number of persons in building Q = q

If 15 persons are sent from P to Q,

then the number of persons in each building is the same

=> p-15 = q+15

=> p - q = 30 ----(Equation 1)

If 20 persons are sent from Q to P,

then the number of persons in P is double the number of persons in Q

=> 2(q - 20) = (p + 20)

=> 2q - 40 = p + 20

=> 2q - p = 60 ----(Equation 2)

(Equation 1) + (Equation 2)=> q = 90

From Equation 1, p = 30 + q = 30 + 90 = 120

i.e., Building P has 120 persons

Answer 2

Answer:

Here is your answer.

Answer/Explanation

Answer is C.

Assume the number of persons in building P = p

and the number of persons in building Q = q

If 15 persons are sent from P to Q,

then the number of persons in each building is the same

=> p-15 = q+15

=> p - q = 30 ----(Equation 1)

If 20 persons are sent from Q to P,

then the number of persons in P is double the number of persons in Q

=> 2(q - 20) = (p + 20)

=> 2q - 40 = p + 20

=> 2q - p = 60 ----(Equation 2)

(Equation 1) + (Equation 2)=> q = 90

From Equation 1, p = 30 + q = 30 + 90 = 120

i.e., Building P has 120 persons

Hope it helps you !!