David invested certain amount in three different Schemes A, B and C with the rate of interest 10% p.a., 12% p.a. and 15% p.a. respectively. If the total interest accrued in one year was ₹3200 and the amount invested in Scheme C was 150 % of the amount invested in Scheme A and 240% of the amount invested in Scheme B, what was the amount invested in Scheme B?

Let x, y and z be the amounts invested in schemes A, B and C respectively. Then,

⇒ 10x + 12y + 15z = 320000 ... (i)

Now, z = 240% of y

= ... (ii)

And, z = 150% of x

=

... (iii)

From (i), (ii) and (iii), we have :

16y + 12y + 36y = 320000

⇒ 64y = 320000

⇒ y = 5000.

∴ Sum invested in Scheme B = ₹5000.