During a spring season, a certain lacier surged at the rate of 1 mi

Not tough one.
First we have that 5280=100 days ==> 1 day=52,80 We know that 1 day = 24 hours hence 1 hour = 52,80/24 We don't know exact value but it is clear that this value is slightly more than 2. Hence B is the correct choice

Thanks you once again Engr2012

This is very basic but I aways face difficulties with conversions(specifically distance related problems). For example converting meters into km, or inches into km, or km into m etc. I always get confused with If I should divide or multiply.

Is there any easy rule to remember how conversions should be done? For example anything like, if we convert smaller thing into bigger then we always multiply otherwise divide etc ? Im just brainstorming to make any simple rule to deal with these type of questions. Im posting another sample question below.

The average distance between the Sun and a certain planet is approximately 2.3 x 10^14 inches. Which of the following is closest to the average distance between the Sun and the planet, in kilometers? (1 kilometer is approximately 3.9 x 10^4 inches.)

(A) 7.1 x 10^8
(B) 5.9 x 10^9
(C) 1.6 x 10^10
(D) 1.6 x 10^11
(E) 5.9 x 10^11

So e.g. in order to convert inches into km, I should divide? Can we make any rule out of that?

Thanks,
Harvey

Hi,
you should remember that a smaller quantity of a bigger unit will contain bigger quantity of smaller unit...
so if you apply to inches and km..
a smaller quantity of km will contain bigger quantity of inches...
AND to get a bigger quantity you multiply and to get a smaller quantity you divide..
so
1) multiply when converting from bigger unit to smaller unit... example km to meter, km to inches, m to cm, l to ml etc..
2) divide when converting from smaller unit to bigger unit.... example cm to m, gm to kg, m to km..etc

if you were to solve the above Q, you are converting from smaller unit to bigger unit, so divide..
3.9 x 10^4 inches.=1 kilometer
1 inch=1/3.9 x 10^4 km..
2.3 x 10^14 inches= 2.3 x 10^14 * 1/3.9 x 10^4 km..
approx .6 * 10^10= 6*10^9.. B

\(\frac{5280feet}{100 Days} * \frac{1 Day}{24 hour}\)

\(\frac{5280feet}{2400hours}\)

\(\frac{11}{5}\)

5280 ft per 100 days
52,80 ft per day ≈ 53 ft per day
Now we need to divide 24 hours by the amount of feet per day
53/24≈ 2,20 (2 1/5) = 11/5

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