Ugh, homework help? i asked before but no ones helping!! please!!! 10 points to anyone who at least tries!!!?

Question

i need help with conversions. please please please help!!! i just want to know HOW to do it.

here are the questions:

1. how many milligrams are in 3.90 ounces? (1 lb = 453.6 g) ( 16 oz = 1 lb)

2. if you were paid 5.4 c per second, for your work, how much do you earn in dollars per week?

3. if your rock from mars has a density of 21.076 mg per liter, what is its density in dg per centiliter?

4. Driving in traffic in Europe, your speed is 1600 meters per minute. How fast are you driving in milesper hour? ( 1760 ft = 1 mile) (2.54 cm = 1 inch)

Please help me!!. Thanks

Answer 1

One way to attack this type of problem is to do a "units equation".

Just put in the units without numbers to see if it makes sense,

then go back and add the numbers.

It works better when you can write everything out with

horizontal fraction lines instead of typed /'s.

Give it a try.

1)  milligrams / gram  * grams / lb * lbs / oz

the grams and the lbs cancel, and you're left with mg / oz

Then just multiply by the given number of oz !

1000 mg / g * 453.6 g / lb * 1/16 lbs / oz

1000 * 453.6 * 1/16 = 28350

* 3.90 = 110565

2)

(dollars / cent) * (cents / second) * (seconds / minute) * (minutes / hour) * (hours / week)

1/100 $ / cent * 5.4 cents / sec * 60 secs / min * 60 mins / hr * (24 * 7) hrs / week

5.4 * 60 * 60 * 24 * 7 / 100 = 32659.2  (for working all 168 hours)

For 40 hours it's slightly less than 1/4 of that: $7776

(sanity check: 3600 seconds / hour * 40 hours = 144000,

times $0.054  = $7776 per week)

Nice pay!

3)

dg = 1/10 liter, centiliter = 1/100 liter, mg = 1/1000 liter.

(mg / liter) * (dg / mg) * (liters / centiliter)

21.076 * 1/100 * 100 = 21.076

4)

(meters / minute) * (cm / meter) * (in / cm) * (miles/in) * (minutes / hour)

1600 * 100 * 1/2.54 * (1/(5280*12)) * 60 = 59.65 miles per hour

1600 meters = almost but not quite 1 mile,

and 1 mile per minute = 60 mph

With more practice and understanding you can take shortcuts,

but this method - if you set up correctly - always works.

=

Answer 2

ok i know #2 its 154,432 dollars. cause first you times 5.4 by 60 seconds and then you timesit by 24 and then you times that by 7. ok plz check the answer again cause i didnt do it on the calculator. good luck

Answer 3

i am so sorry this is not the work for my grade