Answer:
6+(5 x 2)+5=21
the way you wrote this was kinda weird so I don't know what you expected as an answer
Step-by-step explanation:
5 x 2=10
10+6=16
16+5=21
21
8 is your range, 15-7= 8.
If Ann can build the model in 3 hours, then in 1 hour she gets 1/3 of it done. Likewise, if Sam can build the model in 6 hours, then in 1 hour he gets 1/6 of it done. We are looking to find how long it takes when they combine their efforts, so we will add the two together and set it equal to 1/x, x being the number of hours it takes for both of them to get the whole job done. The equation then looks like this: 
. You will have to find the common denominator to add those fractions, and once you do, cross multiply to solve for x.
The answer is no relationship (edit)
Answer:
77.2°
Step-by-step explanation:
Consider the triangle JKR.
∠KJR=108.6 (lies on the same line as ∠RJA, angles on a straight line add up to 180)
All the angles in a triangle add up to 180, so:
∠JKR+∠KJR+∠JRK=180
∠JKR+108.6+32.8=180
∠JKR=38.6=∠RKA
Consider ∠RKA. This angle stands on the same arc as ∠RCA.
Since the angle at centre is twice the angle at circumference, 2(∠RKA) = ∠RCA.
2(∠RKA) = ∠RCA
2(38.6)=∠RCA
∠RCA=77.2°
