Select the option that is related to the third number in the same way as the second number is related to the first number and the sixth number is related to the fifth number.
15 : 135 :: 16 : ? :: 18 : 189
Answer & explanation
Correct answer: option 1
15 : 135 :: 16 : ? :: 18 : 189
The logic followed here is :
{( FIRST NUMBER +3 ) × ( FIRST NUMBER)} ÷ 2 = IIND NUMBER
AS
{( 15 +3 ) × ( 15)} ÷ 2
= {18 × ( 15)} ÷ 2
= 9 × 15
= 135
AND
{( 18 +3 ) × ( 18)} ÷ 2
= {21 × ( 18)} ÷ 2
= 9 × 21
= 189
SIMILARLY
{( 16 + 3 ) × ( 16)} ÷ 2
= {19 × ( 16)} ÷ 2
= 19 × 8
= 152