Question

17.
A took 40% of a sum at the rate of 15% p. a. 50% of the
remaining sum at the rate of 10% p. a. and the remaining sum
at the rate of 18% p. a. What is the rate of interest p. a. on the
whole sum?
A 160 TT
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कारगर​

Answer 1

$\huge \fbox \purple{❥ Answer}$

Let the amount be Rs.x

Investment is done as given below.

Amount left = x−40100x=60x100

40100x at 15% p.a.

50100of 60x100=30x100 at 10% p.a.

Rest amount

=x−40x100−30x100=3x100 at 18% p.a.

Interest earned by each at end of 1 yeas

By 1st => 15100×40x100=601000x

By 2nd => 10100×30x100=301000x

By 3rd => 18100×30x100=541000x

Total interest = 1441000x

Therefore, Rate % = 144x1000x×100 = 14.4%