Explanation

Men       Day

10           48

6             x

*****

Men       Day

10           x

6             48

****

6x = 480

x = 80

Explanation

Given numbers:
0.1, 0.21, 0.31, 0.41, 0.51

Step 1: Add all the numbers

$$0.1 + 0.21 + 0.31 + 0.41 + 0.51 = 1.54$$

Step 2: Divide by the number of values

$$frac{1.54}{5} = 0.308$$

Explanation

Total marks of 28 students in Mathematics = 28 x 50 = 1400

New number of students = 28 - 8 = 20

New average of marks in Mathematics = 50 + 5 = 55

∴

Total marks of 20 students in Mathematics = 20 x 55 = 1100

∴

Total marks of 8 students who left the school = 1400 - 1100 = 300

∴

Average marks of these 8 students = 

300/8 = 37.5

Explanation

To find the average, we need to convert each fraction to a decimal, add them up, and then divide by the number of fractions.

Here are the fractions converted to decimals:

1.  1/2 = 0.5
2.  5/6 = 0.83 (rounded to two decimal places)
3.  3/4 = 0.75

 5/12 = 0.42 (rounded to two decimal places)

Now, let's add them up:

0.5 + 0.83 + 0.75 + 0.42 = 2.5

Finally, let's divide by the number of fractions (4):

2.5 ÷ 4 = 0.625

To convert this back to a fraction, we get:

0.625 = 5/8

Explanation

 Let us assume that Haroon uses X units of petrol everyday.

So the amount of petrol in the tank when it is fuel will be 10X.

If he started using 25% more petrol every day, then the amount of petrol he how uses everyday will be

X (1 +25/100) =1.25x

Therefore, number of days his petrol will how last = Amount of petrol in tank / amount of petrol used everyday = 10x/1.25x = 10/1.25 = 8 Days

Explanation

Given:

Average = 18

Numbers: 7, 13, 17, x, 29

Average = (Sum of numbers) / (Total count)

18 = (7 + 13 + 17 + x + 29) / 5

Multiply both sides by 5:

90 = 66 + x

x = 90 - 66

x = 24

Explanation

Given:

1. Ten years ago, C's mother was 4 times as old as C:

10 years ago, C = 15 → mother = 4×15 = 60 → Now = 70

After 10 years, mother = 80 → 2×25 = 50

Explanation

To find the sum of the five numbers, we can use the formula for the average:

$$\text{Average}=$$Sum of numbers/ Number of numbers​

Given that the average is 6.92 and there are 5 numbers, we can substitute into the formula:

6.92=Sum of numbers/5​

Multiplying both sides by 5:

$$\text{Sum of numbers}=6.92\times 5=34.6$$

Explanation

Step 1 - The unitary method can be used in order to determine the total amount of yellow paint she needs to mix with 18 ounces of red paint to maintain the same proportion.

Step 2 - Let the total amount of yellow paint she needs be 'x'.

Step 3 - So, the value of 'x' can be calculated as:

x = 18/8 x 20

Step 4 - Simplify the above expression.

x = 45 ounces.

Explanation

 We are given:

Average of 6 numbers = 10

So, total sum = 10 × 6 = 60

If each number is multiplied by 3, then the new total becomes:

New total = 60 × 3 = 180

Number of values = still 6

New average = 180 ÷ 6 = 30