Answer:
2069.
Step-by-step explanation:
Let Devyani's age in 2073= x years and y be her fathers age Then:
y = 7x
- and in 8 years time ( 2081) we have:
y + 8 = 3(x + 8)
y = 3x + 24 - 8
y = 3x + 16. Eliminating y from the 2 equations:
7x = 3x + 16
4x = 16
x = 4.
So in 2073 she was 4 years old
Therefore she was born in 2069.
Answer:

Step-by-step explanation:
The function is
where x is the number of bottles of soda.
The domain means the set of "allowed" x values.
Also, f(x) means the amount of money left, which cannot be less than 0. So we put 0 into f(x) and solve for x:

This means the highest number of bottles you can buy is 10. So the domain is anything from 0 to 10. <em>You can buy 0 until highest 10 bottles. Hence the domain is </em>

<span>The given function is f(x) = (7x + 1)/2. Write it as y = (7x)/2 + 1/2. To determine the inverse do these 3 steps. Step 1: Swap x and y to obtain x = (7y)/2 + 1/2. Step2: Solve for y. First, multiply through by 2 to obtain 2x = 7y + 1. Second, subtract 1 from each side to ontain 2x - 1 = 7y. Third, divide through by 7 to obtain (2x - 1)/7 = y. Step 3: Set y to the inverse of f(x) to obtain f^(-1) (x) = (2x - 1)/7.</span>
Answer:
(1) C
(2) D
(3) B
(4) B
(5) C
Step-by-step explanation:
(1) % decrease = change in price/initial price × 100 = (25 -20)/25 × 100 = 5/25 × 100 = 20
(2) Number of correct answers he answered in the second test = 150 + (30/100 × 150) = 150 + 45 = 195
(3) Let the number be y
3(y + 2) = 24
y + 2 = 24/3 = 8
y + 2 = 8
y = 8 - 2 = 6
(4) Let my father's age be f, my brother's age be b and my age be m
From the first statement
f/5 = b/3 ----- eqn (1)
From the second statement
b = m + 3 ----- eqn (2)
From the third statement
f = 2m - 3 ------ eqn (3)
Substitute the expression of b and f in eqn 2 & 3 into eqn 1
(2m - 3)/5 = (m + 3)/3
3(2m - 3) = 5(m + 3)
6m - 9 = 5m + 15
6m - 5m = 15 + 9
m = 24
Substitute the value of m into eqn 3
f = 2m - 3 = 2(24) - 3 = 48 - 3 = 45
(5) (x - 2)/4 - (3x + 5)/7 = -3
The LCM of 4 and 7 is 28
Multiply each term in the equation by 28
7(x - 2) -4(3x + 5) = -3(28)
7x - 14 - 12x - 20 = -84
-5x - 34 = -84
-5x = -84 + 34
-5x = -50
x = -50/-5 = 10