Answer:
90 Minutes
Step-by-step explanation:
If he took 27 minutes to do 30% of his homework, then we can reverse the operation to find the total amount
30% is the same as 0.3, therefore you divide 27 by 0.3 because the 100% is 1, so by dividing you'll get the 100%.
Let's apply the law of sine to calculate angle C
sin(81)/26 = sin(C)/28
0.1646 = sin(C)/28 and sin(C) =1.063. Sine sin(α) cannot be > than 1, so this triangle is invalid
18 = 10 + 2k
move 10 to the other side
sign changes from +10 to -10
18-10=10-10+2k
18-10= 2k
8= 2k
divide by 2 to get k by itself
8/2= 2k/2
Cross out 2 and 2 , divide by 2 and then becomes 1*1*k= k
k=8/2
Answer: k= 4
19. B.
20. J.
Hope this helps :P