You can solve this one by adding their rates, but you have to invert the numbers they give you to find the rate. Rate is measured in something per unit of time, and "per" indicates division. So the rates are: 1/3 of an hour (Sally) and 1/6 of an hour (Steve). So add the rates: 1/3 + 1/6 = 1/2. (1/3 is 2/6, and 2/6 + 1/6 = 3/6). Since their combined rate is 1/2 of a room in one hour, it takes them two hours to paint the room.
This answer makes sense: It takes Sally three hours by herself; with Steve's help, she's faster, but not THAT much faster, because he's pretty slow. You can often spot-check word problem answers like this by giving it a common sense once-over. If we came up with four hours, that would clearly be wrong: it should take her LONGER if she's getting help.
Answer:
the answer is C: 1932 sq. cm
Step-by-step explanation:
You want to break down the sections (which is double for each)
there are 6 rectangles but you will only need to calculate for 3
1st rectangle
a = (25) (12)
a = 300 sq. cm
**then multiply by 2 = 600 sq. cm**
2nd rectangle
a = (12) (18)
a = 216 sq. cm
then 216 * 2 = 432 sq. cm
3rd rectangle
a = (25) (18)
a = 450 sq. cm
then 450 * 2 = 900 sq. cm
Total Surface Area
SA = 600 sq. cm + 432 sq. cm + 900 sq. cm
SA = 1932 sq. cm
Statement A is the false one.
Answer: 585 miles
Step-by-step explanation: 60 x 7 for the first 7 hours = 420 miles, then 3 x 55 for the last 3 hours = 165 add them together, 420+265 you get= <u>585</u>
