Answer:
Step-by-step explanation:
Let the age be xy or 10x + y.
Reverse the two digits of my age, divide by three, add 20, and the result is my age, convert this to equation:
- (10y + x)/3 + 20 = 10x + y
- (10y + x)/3 = 10x + y - 20
- 10y + x = 3(10x + y - 20)
- 10y + x = 30x + 3y - 60
- 30x - x + 3y - 10y = 60
- 29x - 7y = 60
We should consider both x and y are between 1 and 9 since both the age and its reverse are 2-digit numbers.
Possible options for x are:
- 29x ≥ 7*1 + 60 = 67 ⇒ x > 2, at minimum value of y,
and
- 29x ≤ 7*9 + 60 = 123 ⇒ x < 5, at maximum value of y.
So x can be 3 or 4.
<h3>If x = 3</h3>
- 29*3 - 7y = 60
- 87 - 7y = 60
- 7y = 27
- y = 27/7, discarded as fraction.
<h3>If x = 4</h3>
- 29*4 - 7y = 60
- 116 - 7y = 60
- 7y = 56
- y = 8
So the age is 48.
Answer:
6.73 X 10 to the sixth power.
1.33 X 10 to the fifth power.
9.77 X 10 to the twenty-second power.
Step-by-step explanation:
Answer:
Gina is 12 years old
Step-by-step explanation:
First, we will have to write these statements mathematically and then solve.
Let Gina's age be x, let Gina's brother's age be y and let Gina's sister's age be z.
The second statement"Gina's older sister is twice Gina's age" can be mathematically written as: z =2 x ---------------------------(1)
The next statement "Gina's brother is half Gina's age" can be mathematically written as y = 
---------------------------------------(2)
Then the next statement "the sum of their ages is 42" can be mathematically written as: x + y + z = 42 ----------------------------(3)
We can now proceed to solve;
Substitute equation (1) and equation(2) into equation (3)
x + y + z = 42
x + + 2x = 42
Multiply through by 2
2x + x + 4x = 84
7x = 84
Divide both-side of the equation by 7
= 
x = 12
Therefore, Gina is 12 years old
Answer:
I have attached the work to your problem.
Please see the attachment below.
I hope this helps!
The length of hours Gilbert drove is 7.5 hours.
The length of hours Brian drove is 4.1 hours.
<u>Step-by-step explanation</u>:
- Gilbert averaged = 45 miles per hour
- Brain averaged = 65 miles per hour
- Total hours = 11.6 hours
- Total distance = 604 miles
Let 'x' be the hours Gilbert drove.
Let 'y' be the hours Brian drove.
x+y = 11.6 -----(1)
45x+65y = 604 -----(2)
Multiply (1) by 45 and subtract (2) from (1)
45x+45y = 522
-(<u>45x+65y = 604</u>)
<u> -20y = -82 </u>
y = 82/20
y = 4.1 hours
The length of hours Brian drove = 4.1 hours
Substitute y=4.1 in (1)
x+4.1 = 11.6
x = 7.5 hours
The length of hours Gilbert drove = 7.5 hours
