Question

the sum of the cost of one maths book, one physics book and one chemistry book is rs. 420. the total cost of one maths book 2 physics book and one chemistry book is rs 480. also the cost of one maths book, 2 pysics book and 2 chemistry book is rs 600. find the cost of each book​

Answer 1

Answer:

X = 240

Y = 60

Z = 120

Step-by-step explanation:

Let's take

one maths book =x

one physics book =y

one chemistry book =z

ATQ,

• eq.1 = x+y+z=420
• eq.2= x+2y+z=480
• eq.3= x+2y+2z=600

We can write equation 2 as x+y+z+y=480

then by subtracting eq1 by eq2

x-x+y-y+z-z+y = 480-420

y = 60

Now subtracting eq2 by eq3

x-x+2y-2y+2z-z = 600-480

z = 120

Now by putting values in eq1

x+60+120=420

x+180=420

x = 420-180

x = 240