Robert Bosch Averages Quiz-4

Explanation:
No. of observations = 10,
Increased average = 3.6,
Total increased value = 10 × 3.6 = 36

Now, let the unit digit of the number whose digits have been interchanged = X and Ten's digit of the number = Y

Original number = (10Y + X), Number after interchanging the digits = (10X + Y)

So, (10X + Y) – (10Y + X) = 36 OR 9X – 9Y = 36
(X-Y) = \frac{36}{9} = 4

The difference between the digits of the 2- digits number is 4.

Explanation:
Total boxes = 17 + 18 = 35 boxes
Increment in average = 92 + 3 = 95 kg

Now, Weight of 18 new boxes = 95 × 35 – 17 × 92 = 1761 kg
Required Average = \frac{1761}{18} = 97.8 Kg

Explanation:
Total monthly income of 4 members = 15130 × 4 = Rs. 60520

Except daughter, total monthly income of 3 members = 14660 × 3 = Rs. 43980

∴ Monthly income of married daughter = 60520 – 43980 = Rs. 16540

Explanation:
Price of Mineral Water in first year = Rs. 7.50 per litre.
∴ Quantity of Mineral water in first year,
= \frac{4080}{7.50}= 544Litres

Price of Mineral water in second year = Rs. 8.00 per litre.
∴ Quantity of mineral water in second year,
= \frac{4080}{8.00}= 510Litres

Price of mineral water in third year = Rs. 8.50 per litre.
∴ Quantity of Mineral water in third year,
= \frac{4080}{8.50}= 480Litres

Required Average = \frac{3\times 4080}{544+510+480}
= = \frac{12240}{1534}=7.98
=Rs 7.98

Explanation:
According to the ShortCut Approach:
ValueOf(\frac{n+1}{2})Result = (\frac{n+1}{2}\times (b+c) - n\times a)
Where,
n is the total number of days= 7 days
b is the average of first four days = 25
c is the average of last four days = 25.5
a is the average of whole days = 25.2

=(\frac{8}{2})\times (50.5)-176.4
202 - 176.4 = 25.6°C

Explanation:
Total number of marks = 88 × 6 = 528
Now, 528 – 86 + 68 = 510
Required Average=\frac{510}{6}=85

Explanation:
Let, the expenditure of ninth person = $ X.
Total expenditure of 8 persons = 8 × 30 = $ 240

According to the question,
X - \frac{X+240}{9} = 20
9X – X – 240 = 180
8X = 180 + 240 = 420
X=\frac{420}{8} = 52.5[/latex]
= $ 52.5
Now, Total expenses = $ 240 + $ 52.5
= $ 292.5

Explanation:
The total age of Leonard’s all family members = 30 × 14 = 420
New baby born and after 4 years the total age of all the members = 420 + 15 × 4
= 420 + 60 = 480
Required Average=\frac{480}{15} = 32 Years[/latex]

Explanation:
According to the question,
20 × 30 + A × 35 + (A + 4) × 25 = 29.6 × (20 + A + A + 4)
600 + 35A + 25A + 100 = 29.6 × (24 + 2A)
700 + 60A = 710.4 + 59.2A
710.4 – 700 = 60A – 59.2A
10.4 = 0.8A , A = 13
Quantity of spaghetti that is bought at Rs 25 per kg = 13 + 4 = 17 kg

Explanation:
Total sales = Rs. 38000.
The total sales from 20 outlets = 20 × 400 = Rs. 8000.
The total sales from 10 outlets = 10 × 900 = Rs. 9000
The total sales of the remaining 30 outlets,
= Rs. (38000 – 8000 – 9000) = Rs. 21000
AverageSales=\frac{21000}{30} = 700[/latex]