Question

if raju give 20x+30y money is given to an old man and he gave back 300 rs back . the old man does not take any money then he gave to an uncle 20y+30x money the uncle gave him 900 rs back. find the x and y​

Answer 1

Answer:

Step-by-step explanation:

raju gave 20x+30y money to old man

old man gave back 300 rs to raju

so,  20x+30y=300--------(1)

old man gave 20y+30x money to uncle

uncle gave back 900 rs to old man

so,  20y+30x=900--------(2)

solving (1) and (2)

⇒20x+30y=300

⇒30x+20y=900

⇒3(20x+30y)=3(300)

⇒2(30x+20y)=2(900)

⇒60x+90y=900

⇒60x+40y=1800-------------(3)

multiply minus on both the sides in(3)

⇒ 60x+90y=900

⇒ -60x-40y=-1800

⇒50y=-900

⇒y=-900/50

⇒y=-18---------(4)

now put (4) in (1)

⇒20x-30(18)=300

⇒20x-540=300

⇒20x=300+540

⇒20x=840

⇒x=840/20

⇒x=42

∴ x=42 and y=-18

hope you understood