Question

Expanded form of 51280 is $5\times {10}^4+1\times {10}^a+2\times {10}^2+8\times {10}^b+0$.
Find the value of a and b.

• A. a=4,b=2
• B. a=1,b=3
• C. a=3,b=1
• D. a=3,b=2

Answer 1

The correct option is C a=3,b=1

Given $51280=5\times {10}^4+1\times {10}^a+2\times {10}^2+8\times {10}^b+0$

51280 can be written as
$5\times 10000+1\times 1000+2\times 100+8\times 10+0$
$\Rightarrow$$5\times {10}^4+1\times {10}^3+2\times {10}^2+8\times {10}^1+0$

Comparing the two expressions , we get the value of a=3 and b=1.