Question

Three numbers a,b,care in ratio 1:2:3. their average is 600. if a is increased by 10% and b is increased by 20%, then to get the average increased by 5%, c will increased by

Answer 1

c will decreased by 7%

Step-by-step explanation:

Let the common factor of three numbers is x.

Given:

• Three numbers a,b,c are in ratio 1:2:3 and their average is 600.

$\rightarrow \: \frac{x + 2x + 3 x}{3} = 600 \\ \rightarrow \: 6x = 600 \times 3 \\ \rightarrow \: x = 300$

The three numbers are

a=300

b=600

c=900

• a is increased by 10% and b is increased by 20%, then to get the average increased by 5%.

$\rightarrow \: \frac{1.1a + 1.2b + yc }{3} = 1.05 \times avg \\ \rightarrow \: \frac{1.1 \times 300 + 1.2 \times 600 + y \times 900 }{3} = 1.05 \times 600 \\ \rightarrow 330 + 720 + 900y = 630 \times 3 \\ \rightarrow \: 1050 + 900y = 1890 \\ \rightarrow \: 900y = 840 \\ \rightarrow \: y = 0.93$

c will decreased by 7%.

Answer 2

C will decreased by about 6.67%.

Step-by-step explanation:

Given:

Three numbers a,b,c are in ratio 1:2:3. their average is 600. if a is increased by 10% and b is increased by 20%, then to get the average increased by 5%, c will increased by

Solution:  

Let the ratio of a, b, c be x, 2x and 3x

X + 2x + 3x = 600 $\times$ 3 = 1800

6x = 1800

x = a = 300, b = 2x = 600, c = 3x = 900

Now,

A = 300 $\times$ 110% = 330

B = 600 $\times$ 12% = 720

C = ?

New sum = $3 \times 600 \times 105%$%= 1890

C = 1890 – (330 + 720 ) = 840

C decreases by $\frac{60}{900} \times$ 100 = 6.67% .

To know more:

3a=25bc; if b and c each are doubled, then a will be increased by

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