Question

Quantitative Aptitude Question 6 of 20 If AB = 3:4, B.C = 5.7, C D = 8:9, what is the ratio between A and D. 0 37 0 73 O 21:10 O 10:21​

Answer 1

To find a : b : c, b is made same in both the ratios. L.C.M of 4 and 5 is 20

$a:b=43=4×53×5=2015</p><p>b:c=95=9×45×4=3620</p><p></p><p></p><p>$

∴ a:b:c=15:20:36

Answer 2

A:D = 10:21

Explanation:

Given:

A:B = 3:4

B:C = 5:7

C:D = 8:9

To find:

The ratio between A and D

Solution:

==> Comparing A:B and B:C

==> B is common for both the values

==> B value must be same

==> A:B = 3:4

==> B:C = 5:7

==> LCM for B is 20

==> Multiply by 5

==> A:B = 5(3:4)

==> A:B = 15:20

==> Multiply by 4

==> B:C = 4(5:7)

==> B:C = 20:28

==> B is common

==> A:B:C = 15:20:28

==> Comparing A:B:C and C:D

==> C is common for both the values

==> C value must be same

==> A:B:C = 15:20:28

==> C:D = 8:9

==> LCM for C is 224

==> Multiply by 8

==> A:B:C = 8(15:20:28)

==> A:B:C = 120: 160:224

==> Multiply by 28

==> C:D = 28(8:9)

==> C:D = 224: 252

==> C is common

==> A:B:C and C:D = 120:160:224 and 224:252

==> A:B:C:D = 120:160:224:252

==> A:B:C:D = 60:80:122:126

==> A:B:C:D = 30:40:62:63

==> Find the ratio between A and D

==> A:D = 30:63

==> A:D = 10:21