Correct option is D
Given:
The cost of keyboard and a mouse =₹3600
The cost of keyboard is 7 times that of mouse
Solution:
Let the cost of mouse be x
Then cost of keyboard = 7x
According to question:
x +7x =3600
8x = 3600
x= ₹450
Cost of mouse = ₹450
Cost of keyboard = 7x = 7 450 = ₹3150