Question

An object was launched from a place P in constant speed to hit a target. At the 15^th second, it was 1400 m from the target, and at the 18^th second 800 m away. Find the distance covered by it in 15 seconds

Answer 1

Let us take the time T along the x-axis and the Distance D along the y-axis.

Given when time T = 15s, the distance D = 1400 m

The corresponding point is (15, 1400)

Also when time T = 18s, the distance D = 800 m.

The corresponding point is (18, 800)

The distance covered by it in 15 seconds:

Put T = 15 in the above equation

15 = `(1400 - "D")/200 + 15`

∴ `(1400 - "D")/200` = 0

⇒ D = 1400 m.