**11) Of three numbers, the third is twice the second and the second is 4 times the first. If their average is 78, the smallest of the three numbers is:**

**Answer:** 18

**Explanation:**

Let first number be x.

So,2nd no. = 4x & 3rd no.=8x.

So,x+4x+8x=78 × 3 = 234.

13x = 234

x = 234/13

Hence,smallest Number x=18.

**12) A man spends Rs. 1600 per month on an average for the first three months, Rs 1550 for next four months and Rs. 1800 per month for the last five months and saves Rs . 5200 a year. What is his average monthly income?**

**Answer:** Rs. 2100

**Explanation:**

Total expenditure for the first 3 months = 3 × 1600 = 4800

Total expenditure for 4 months = 4 × 1550 = 6200

Total expenditure for 5 months = 5 × 1800 = 9000

Total expenditure and saving (which is income for one year)

= 4800 + 6200 + 9000 + 5200 = Rs. 25200

So, Average monthly income = 25200/12 = Rs. 2100

**13) The average temperature for Monday, Tuesday and Wednsday is 36.3 degrees C. The average temperature for Tuesday, Wednesday and Thursday is 36.7 degrees C. if Monday’s temperature recorded as 39 degrees c, find the Thursday’s temperature ?**

**Answer:** 40.2 degrees C

**Explanation:**

MOn + Tue + wed Temperature = 3X36.3 = 108.9

Tue + wed Temperature = 108.9 – 39 = 69.9

Tue + wed + Thu temperature = 3X36.7 = 110.1

So, Thursday’s temperature = 110.1 – 69.9 = 40.2 degrees C

**14) The average weight of 8 persons increases by 1.5kg when a person weighting 65kg is replaced by a new person. What could be the weight of the new person?**

**Answer:** 77kg

**Explanation**:

Let the average weight of 8 persons be ‘x’

years and the age of the new person be ‘y’ years

so, (8x – 65 + y) / 8 = x+1.5

so, y = 77kgs

65 + 8X1.5 = 77kgs

**15) In a hostel of 12 boys and some girls, an average consumption of rice per month is 12 kg, while the Average consumption for boys is 16 kg per head and for girls 8 kg per head. The number of girls in The hostel?**

**Answer:** 12

**Explanation:**

Number of girls — G

(12+G) × 12 = (12 × 16)+(8 × G)

144 + 12G = 192 + 8G

12G − 8G = 192 − 144

4G = 48

G = 12.