Question

What is the result of adding 2.5 × 103 and 3.5 × 102?
a. 2.9 × 103
b. 6.0 × 105
c. 6.0 × 103
d. 2.9 × 102

Answer 1

2.5×103 and 3.5 x 102=6.0x103

Answer 2

Answer:

The correct answer is option (a).

Explanation:

$(2.5\times 10^3)+(3.5\times 10^2$

Taking $10^2$ common form both brackets:

$=10^2((2.5\times 10)+(3.5\times 1))$

Taking 5 common form both brackets:

$=10^2\times 5((0.5\times 10)+(0.7\times 1))$

$=10^2\times 5(5.0+0.7)=10^2\times (28.5)$

$=2.85\times 10^3\approx 2.9 10^3$[

Hence,the correct answer is option (a).