Question

( 5 ) The total cost of 5 pens and 2 books is Rs 150, while the total cost of 7 pens and 3 books is Rs 219. Find the total cost of 3 pens and 1 book.
only in elimination method please​

Answer 1

Answer:

Let the cost of one pen be RsX/- and cost of one book be RsY/-

Now ATQ,

5X + 2Y = 150

7X + 3Y = 219

By eliminating both the equations we get,

15X + 6Y =450

14X + 6Y = 438

-. -. -

______________

X. = 12

______________

put X = 12 in equation 1,

60 + 2Y = 150

Y = 90÷2 = 45

hence, cost of 3 pens = 3×12 = Rs36/-

cost of 1 book = 1×48 = Rs48/-

Therefore, total cost = Rs(36+48)/-

= Rs84/-