Answer:
35/100
Step-by-step explanation:
P(green or black) = 3/20 + 4/20 = 7/20
7/20 = 35/100
120+.5x=50+.7x
Subtract 50 from both sides and then subtract .5x from both sides to get 70=.2x. Then divide both sides by .2 to get x=350.
Answer:
p = 497 ( to the nearest whole number)
Step-by-step explanation:
In order to do this calculation, we will apply the principle of accounting, where a certain amount is compounded periodically and yielding a future value. Compound interest is used because the percentage growth rate is added on the new amount gotten each year, and not on the first or original amount.
Hence:
FV = PV × 
where FV = future value = population in 2020 = 810
PV = present value = population in 2010 = p
r = percentage growth rate in decimal = 5% = 5/100 = 0.05
n = growth rate period per year = once = 1
t = time in years = 2010 to 2020 = 10 years
∴ 
(dividing both sides by 1.6289)
p = 810 ÷ 1.6289 = 497.2 = 497 (to the nearest whole number)
∴ population in 2010 = 497