GATE-2018 (24) :Wyllie – Time average equation

1.If the Atlantic Ocean is widening at a rate of 3 cm per year how far (in kilometers) will it spread in a million years?

(A)300 kilometers (B) 30 kilometers (C)30 miles (D)3 kilometers

Solution:

Atlantic ocean is widening at a rate of 3 cm/year

Therefore,

3 cm ------------------1 year

? ----------------------10⁶ years (or) 1 million year

Cross multiplying the above one

x* 1 year = 10⁶ * 3 cm

==> x= (10⁶ * 3 )/ 1

==> x= 3000000 cm

==> x= 30 km

In 1 million year Atlantic ocean is widening 30 km.