Question

Compute the following differences $(10.4\times 9.6)-(10.6\times 9.4)$

• A. 0.6
• B. 0.2
• C. 0.4
• D. 0.8

Answer 1

The correct option is B

0.2

The given expression is

$(10.4\times 9.6)-(10.6\times 9.4)$

$=\left[\right(10+0.4)\times (10-0.4\left)\right]-\left[\right(10+0.6)\times (10-0.6\left)\right]$

$=[{10}^2-(0.4{)}^2]-\left[\right(10{)}^2-\left(0.6{)}^2\right](a+b)(a-b)=a^2-b^2$

$=(10{)}^2-(0.4{)}^2-(10{)}^2+(0.6{)}^2$

$=(0.6{)}^2-(0.4{)}^2$

$=(0.6-0.4)(0.6+0.4)$

$=0.2\times 1$

$=0.2$