Answer:
y = 5 e^r * t
Let y be the population in billions and t the value of elapsed years
7 = 5 e^r * t is the equation being used where t = 15
7/5 = e^r * t
ln 7/5 = r * t taking ln of both sides
r = .336 / 15 = .0224
y = 5 e^(.0224 t) is then our equation
Check - suppose you want y at 2020
y = 5 e^(.0224 * 20) would be the equation
y = 5 e^.449 = 7.83 billion - seems to be a reasonable answer
45% of what number is 27
0.45x = 27
x = 27 / 0.45
x = 60 <== 45% of 60 = 27
Multiply 6 by 2 and add 6cm. the radius is half of the diameter so just multiply by two and add the number.
1/8 ÷ 4 =
1/8 × 1/4 = 1/32
Multiply the reciprocal
√99 is an irrational number
