Answer:
The youngest person is 2 years old
Step-by-step explanation:
There are six people at a bus stop.
We are told that:
The mean age of the group is 21.
The total number of people is 6 people
Hence:
The total sum of their ages is 21 × 6
= 126
Each person is half the age of the next person in line.
Let the age of the first person be = x
The age of the second person = x/2
The age of the third person = x/2 ÷ 2 = x/2 × 1/2 = x/4
The age of the fourth person = x/4 ÷ 2
x/4 × 1/2 = x/8
The age of the fifth person = x/8 ÷ 2
x/8 × 1/2 = x/16
The age of the sixth person = x/16 ÷ 2
x/16 × 1/2 = x/32
Hence:
x + x/ 2 + x/4 + x/8 + x/16 + x/32 = 126
Lowest Common Denominator is 32
32x + 16x + 8x + 4x + 2x + x/32 = 126
63x /32 = 126
Cross Multiply
63x = 126 × 32
63x = 4032
x = 4032 /63
x = 64 years
Hence, the age of the first person is 64 years.
The age of the youngest person which is the sixth person is :
x/32
= 64/32
= 2 years
