First of all you need to work out 20 minutes in hours, this can be done by dividing 20 by 60:
20/60 = 1/3
Then you need to divide 15 by 1/3 to get the final speed:
15 / 1/3 = 45 miles per hour
He will need to be traveling at 45 miles per hour,
Hope this helps! :)
<span>C) 320 15/16 in3 ..........................................</span>
Answer:
See below.
Step-by-step explanation:
Convert the cotangent to cosine over sine:
Use the cofunction identities. The cofunction identities are:
To convert this, factor out a negative one from the cosine and sine.
Recall that since cosine is an even function, we can remove the negative. Since sine is an odd function, we can move the negative outside:
Since if he gets the driveway done in 20 minutes he gets 1/20th of the driveway done in 1 minute (if x=20 then x/20=1 by dividing both sides by 20) and if his brother gets 1/12th of the driveway done in one minute, then if t represents the time it takes to shovel the driveway, t/20+t/12=1 driveway shoveled as 1/20+1/12=amount they can do in 1 minute, so t/20+t/12 is how much they can do in t minutes. Multiplying both sides by 20*12=240, we get 12t+20t=32t=240. Dividing both sides by 32, we get 240/32=7.5 minutes to shovel the driveway.
