Answer:
Step-by-step explanation:
t = mr^2/3
Divide both sides by r^2/3
m = t / r^2/3
Answer:
10 spiders and 12 ants
Step-by-step explanation:
You need to create two equations
s = # of spiders
a = # of ants
s + a = 22 heads
since each spider and ant has one head
8s + 6a = 152 legs
since every spider has 8 legs and every ant has 6
s + a = 22 can be turned into s = 22 - a
now use substitution
8(22 - a) + 6a = 152
176 - 8a + 6a = 152
176 - 2a = 152
24 = 2a
a = 12
now that you have the number of ants you can solve for the number of spiders
s + a = 22
s + 12 = 22
s = 10
Let Daniel's age be 'x' years , hence, Lisa's age is (x - 5) years. Let Grandma's age be 'y' = 54 years.
Hence,
x(x - 5) = 2/3 × y
x² - 5x = 2 × 54 years / 3
x² - 5x = 36 years
x² - 5x - 36 = 0
∆ = (-5)² - 4(1)(-36) = 25 + 144 = 169
√∆ = √169 = 13
x1 = (5+13)/2, x2 = (5-13)/2
x1 = 9, x2 = -4
Since, age can't be negative,
Daniel's age = x = 9 years.