Answer:
7 years
Step-by-step explanation:
Given that:
Let Richard's age = x
Elder sister's age = 2x
Youngwr sister's age = x - 2
Product of sisters ages = 70
2x * (x - 2) = 70
2x² - 4x = 70
2x² - 4x - 70 = 0
x² - 2x - 35 = 0
x² - 7x + 5x - 35 = 0
x(x - 7) +5(x - 7) = 0
(x - 7) or (x + 5) = 0
x = 7 or x = - 5
X can't be negative
Hence, x = 7
Richard is 7 years
Answer:
70 apples
Step-by-step explanation:
We can use a ratio to solve
7 apples x apples
-------------- = -------------
50 name 500 names
Using cross products
7 * 500 = 50x
Divide by 50
7 * 500/50 = 50x/50
70 =x
If b is the base then the height h=b+6. As we have S=bh/2 then
36=b(b+6)/2;
b²+6b-72=0;
D/4=3²+72=81
b₁=-3-9=-12
b₂=-3+9=6.
The base is always positive so b=6, h=6+6=12.
Answer: base=6 ft, height=12 ft.
