physics problem

a person walks up a stalled escalator in 90 sec.W HEN STANDING ON THE SAME ESCALATOR,NOW MOVING,HE IS CARRIED IN 60 SEC.THE TIME HE WOULD TAKE TO WALK UP THE MOVING ESCALATOR? A)27S B) 72S C)18S D) 36S E)48S

#Physics #HelpMe!

Easy Math Editor

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Remember to wrap math in `$` ... `$` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
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`\boxed{123}`	$\boxed{123}$

Comments

Tan Li Xuan - 8 years ago

thank u very much .........but i would like to know the steps too...... how did u do it?

Sonali Sukesh - 8 years ago

Assume that the length of the escalator is $1$ ,the speed at which the person walks is $\frac{1} {90}$ and the speed of the escalator is $\frac{1} {60}$ .So,the speed at which he moves up the moving escalator is $\frac{1} {90} +\frac{1} {60} =\frac{5} {180}=\frac{1} {36}$ .So,it takes 36 seconds for him to walk up the moving escalator.

Tan Li Xuan - 8 years ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$