Reena has pens and pencils which together are 40 in number. If she has 5 more pencils and 5 less pens, the number of pencils would become 4 times the number of pens.Find the original number of pens and pencils.

2
by dweejareddy

2014-10-04T16:48:13+05:30

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Let number of pens = x
pencils = y

x+y=40   <<<<<<<<<<< eqn(1)

(x+5) = 4(y-5)
⇒ x+5 = 4y - 20
⇒ x = 4y -25

Putting in eqn(1)
x+y=40
⇒4y-25+y = 40
⇒5y = 40+25
⇒5y = 65
⇒ y = 65/5 = 13

x = 40-13=27

No. of pencils = 27
No.of pens = 13
2014-10-04T16:51:17+05:30

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Let us say Reena has P number of pens and N number of pencils.

As the total number is 40 ,      P + N = 40
N = 40 - P      ---- equation 1

If she has 5 more pencils, it means number of pencils = N + 5
If she has 5 less pens, it means number of pens = P - 5

Then number of pencils becomes 4 times the number of pens.  That is,
N + 5 =  4 * (P - 5)
so   N + 5  =  4 P - 4 * 5 = 4 P - 20
so    N = 4 P - 25

Substitute N = 40 -P from equation 1,
N = 40 - P = 4 P  - 25

40 + 25 = 4 P + P                or                     65 = 5 P

P = 13
from equation 1,   N = 40 - P = 27

She has 27 pencils and 13 pens.