After 5 months of saving money, nikki had saved $350. she has now been saving for 9 months and has saved $690. find the percent of increase in the amount of nikki's savings. round the percent to the nearest tenth if necessary.

21%

Step-by-step explanation:

for the first 5 months Nikki saved $350 so she saved 70 every month. for the next 4 months she saved 690-350=340, so 85 per month. The rate of increase should be (85-70)/70=.214 round it to the nearest tenth is .21, to find the percentage just multiply 0.21 by 100 you get 21%

(a) the volume of the cone is 20/3 in3

hence, option a is correct.