How to Simplify ?

Question

$\frac{1}{10^{9}}[30*10^{-3}]+(1-\frac{1}{10^{9}})[300*10^{-9}]$
 

Answer should be in  nano seconds

Comments

is answer 300.029997nsec?? else u can go with 300.03nsec.

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Yeah it is 300.03 .But can u pls provide a step wise solution . Im not getting how to simplify it :(

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 @dulqar, 1/10⁹ = 1 nsec = 1*10^-9 sec.

so first term will become 30* 10^-3  * 10^-9 (because of 1/10⁹)= .03nsec

in second term 300* 10^-9 is given so u can take it as 300nsec

so it will become 300nsec*(1 - (1/10⁹)) == 300nsec*(1 - 10*⁹)

so the -ve term is quite small so we can neglect this term so addtion of 1st and 2ns term is 300nsec + .03nsec