The sum of Ali and Mel's age is 39. If Mel is 3 years younger than twice Ali's age, how old is Mel?

Mathematics

1 answer:

olga55 [171]3 years ago

4 0

Answer:

Age of Mel is 25 years.

Step-by-step explanation:

It is given that,the sum of Ali and Mel's age is 39. If Mel is 3 years younger than twice Ali's age.

Let 'x' be the Ali's age and 'y' be the Mel's age

<u>To find the value of x and y</u>

sum of Ali and Mel's age is 39

⇒ x + y = 39 ------(1)

Mel is 3 years younger than twice Ali's age

⇒ y = 2x - 3 -------(2)

⇒ 2x - y = 3 -----(3)

(1) + (3) ⇒

x + y = 39

2x - y = 3

----------------

3x = 42

x = 42/3 = 14

y = 2x - 3 = 14*2 - 3 = 25

Therefore the age of Ali = 14

Age of Mel = 25

You might be interested in

__,__, 8.16,32,64 what is the arithmetic sequence?

seraphim [82]

Answer:

2,4,8,16,32,64

Step-by-step explanation:

There are a couple of ways one could approach this. The goal is to find out the factor by which the numbers are increasing. Looking at going from 8 -> 16, we have either added 8, or doubled 8. So the factor is either +8 or x2. Going from 16 -> 32, adding 8 no longer holds true, while multiplying by 2 (doubling 16) does. To confirm what we have found, we can further check our math by using the final two numbers, 32 -> 64, to confirm that the sequence pattern is to double the current number to achieve the next number.

Working backwards, we can half each number to find out the first two numbers in the sequence. 64/2 = 32, 32/2 = 16, 16/2 = 8, 8/2 = 4, 4/2 = 2

8 0

3 years ago

How many commuters must be randomly selected to estimate the mean driving time of Chicago commuters? We want 95% confidence that

zimovet [89]

Answer:

61 commuters must be randomly selected to estimate the mean driving time of Chicago commuters.

Step-by-step explanation:

Given : We want 95% confidence that the sample mean is within 3 minutes of the population mean, and the population standard deviation is known to be 12 minutes.

To find : How many commuters must be randomly selected to estimate the mean driving time of Chicago commuters?

Solution :

At 95% confidence the z-value is z=1.96

The sample mean is within 3 minutes of the population mean i.e. margin of error is E=3 minutes

The population standard deviation is s=12 minutes

n is the number of sample

The formula of margin of error is given by,

$E=\frac{s\times z}{\sqrt{n}}$