. The average age of a child in a class of 35 is 11. The average age, including the
teacher is 12. How old is the teacher?
The average weight of a kid in a group of
10 is 35 kilograms. When Sonu also
joined them, the average became 36 kilo-
grams. How much does Sonu weigh?

1) Average age of 35 children = 11

2)Average weight of 10 kids = 35 kg

1) Age of the teacher.

2) Weigh of Sonu.

1) Average age of 35 children = 11

Average age of 35 children including the teacher = 12.

We know that,

Average= sum of observations/Number of observations.

Hence,

→ Sum of ages of 35 children/35 = 11

→ sum of ages of 35 children = 11 * 35

→ sum of ages of 35 children = 385 years

Similarly,

→ (sum of ages of 35 children + age of teacher )/36 = 12

→ 385 + age of teacher = 12 * 36

→ age of teacher = 432 - 385

→ age of teacher = 47 years

Hence, the age of the teacher is 47 years.

2) Average weight of 10 kids = 35 kg

→ sum of weights of 10 kids/10 = 35

→ sum of weights of 10 kids = 10 * 35

→ sum of weights of 10 kids = 350 kg

Also,

When Sonu is joined the average becomes 36 kg.

→ (sum of weights of 10 kids + weight of Sonu)/10 + 1 = 36

→ sum of weights of 10 kids + weight of Sonu = 11 * 36

→ 350 + weight of Sonu = 396

→ weight of Sonu = 396 - 350

→ weight of Sonu = 46 kg

Therefore, the Weight of Sonu is 46 kg.

I hope it will help you.

Regards.

(sum of ages of 35 children + age of teacher )/36 = 12

→ 385 + age of teacher = 12 * 36

→ age of teacher = 432 - 385

→ age of teacher = 47 years

Hence, the age of the teacher is 47 years.

2) Average weight of 10 kids = 35 kg

→ sum of weights of 10 kids/10 = 35

→ sum of weights of 10 kids = 10 * 35

→ sum of weights of 10 kids = 350 kg

Step-by-step explanation:

50 min

step-by-step explanation:

they will be decreasing both their times in half

60 / 2 = 30

40/2 = 20

30 + 20 = 50

87%

step-by-step explanation:

apex answer