CBSE Class 10 Maths Elimination Method

Solution

Let the cost of an orange be Rs. x and that of an apple be Rs. y.

So, 5x + 3y = 35 …(1) 2x + 4y = 28 …(2) 

Multiplying (1) by 2 and (2) by 5,

10x + 6y = 70

10x + 20y = 140 

−14y = −70 y = 5, x = 4 

Solution

Let the tens place number be m and the units place number be n.

m + n = 9 …(i)

According to the question, 10n + m = 10m + n + 63 9n − 9m = 63 n − m = 7 …(ii)

Adding (i) and (ii),

2n = 16

n = 8 and m = 1 

Solution

Let the digit in the tens place be x and the digit in the units place be y.

10x + y + 10y + x = 66

11x + 11y = 66

x + y = 6 …(i)

x − y = 2 …(ii) 

Adding (i) and (ii),

2x = 8 x = 4, y = 2