Management Aptitude Test Feb 2012 Paper

(2) Let number of fridges produced in first year be ‘a’ and production inverse by 'd’ every year. Clearly, production every year will make an AP.
Then, production in the third year,
a + 2d = 600 ...(i)
and production in the seventh year,
a + 6d = 700 ...(ii)
On solving both equations, we get
a = 550, d = 25
Now, total production in 7 yr
= $\frac{\mathit{n}}{2}$ [2a + (n - 1) d] = $\frac{7}{2}$ [2 x 550 + 6 x 25]
= $\frac{7}{2}$ x 1250 = 4375