Answer:
b(b/a)^2
Step-by-step explanation:
Given that the value of the car depreciates such that its value at the end of each year is p % less than its value at the end of the previous year and that car was worth a dollars on December 31, 2010 and was worth b dollars on December 31, 2011, then
b = a - (p% × a) = a(1-p%)
b/a = 1 - p%
p% = 1 - b/a = (a-b)/a
Let the worth of the car on December 31, 2012 be c
then
c = b - (b × p%) = b(1-p%)
Let the worth of the car on December 31, 2013 be d
then
d = c - (c × p%)
d = c(1-p%)
d = b(1-p%)(1-p%)
d = b(1-p%)^2
d = b(1- (a-b)/a)^2
d = b((a-a+b)/a)^2
d = b(b/a)^2 = b^3/a^2
The car's worth on December 31, 2013 = b(b/a)^2 = b^3/a^2
Answer:
11 yrs
Step-by-step explanation:
Mean = sum of ages/number of ages
Let the age of the seventh girl be A
Given the addition of the age of the seventh girl will make the mean of the ages be 13,
So,
13 = 17+8+12+15+15+13+A/7
Add up the ages
13 = 80 + A /7
Cross multiply
80 + A = 13 x 7
80 + A = 91
Subtract 80 from both sides to isolate A
80 - 80 + A = 91 - 80
A = 11
The age of the seventh girl is 11
Answer:
- -3/13 ≈ -1/4
- -6/11 ≈ -1/2
- -7/9 ≈ -3/4
Step-by-step explanation:
We'll drop all the minus signs, since they don't contribute anything but distraction.
When numerators or denominators are relatively large, changing their value by 1 unit will have a relatively small effect on the value of the fraction. For example, ...
3/13 ≈ 3/12 = 1/4
If we compare the decimal values of these fractions, we see that ...
3/13 ≈ 0.230769... (6-digit repeating decimal)
The closest of the offered "reasonable estimate" fractions is 1/4 = 0.25.
__
Likewise, 6/11 ≈ 6/12 = 1/2. In decimal, these fractions are ...
6/11 = 0.54... (2-digit repeat)
1/2 = 0.5
__
We can also increase or decrease both numerator and denominator by the same amount to get a fraction with nearly the same value. This works best when the numbers are larger.
7/9 ≈ 6/8 = 3/4 . . . . . . both numerator and denominator decreased by 1
In decimal, these are ...
7/9 = 0.7... (1-digit repeat)
3/4 = 0.75
0 because you can divide them ie 0 is divisible with 5 and 10
