The total cost of the box and a pen is rs 50 .ifthe cost of 3 boxes is same as the cost of 7 pens ,find the cost of a box and a pen

a box cos 35 and a pen cost 15

Step-by-step explanation:

Interpreting the statement into mathematical equation , from the first statement , let the cost of a box be x and the cost of a pen be y , then

x + y = 50 equation 1

From the second statement

3x = 7y equation 2

Solving the resulting simultaneous equation , we have

From equation 1 , x = 50 - y

substitute this into equation 2 , we have

3(50 - y) = 7y

150 - 3y = 7y

150 = 10y

Therefore : y = 15

substitute y = 15 into equation 3

x = 50 - 15

Therefore x = 35

Therefore , a box cost rs35 and a pen cost rs15