Answer:
The new mean is 77cm
Step-by-step explanation:
If the mean height of the 30 children in a room is 76 cm, then the sum of their ages is
If James with height 107cm joins them, then the total number of children now becomes 30+1=31 and the total height becomes: 2280cm+107cm=2387cm
The new mean now becomes:
Answer:
It takes takes them 31.67 secs to meet after Person A starts walking
OR
34.67 secs after Person B starts walking
Step-by-step explanation:
First, we will find the perimeter of the rectangle
From,
Perimeter of rectangle = 2 ( +
)
Where is the length
and is the breadth
From the question, = 100m
and = 50m
Hence,
Perimeter of the rectangle = 2 (100+50)
= 2(150) = 300m
Hence, the perimeter of the rectangle is 300m
This is the total distance that will be covered by both persons by the time they meet.
Let the distance covered by person A be
and the distance covered by person B be
We can write that
+
= 300m
Velocity of person A, = 4 m/s
and velocity of person B, = 5 m/s
From the question, Person A starts walking 3 seconds after person B,
This means, if person A spends secs before they meet, then person B would spend (3 +
) secs.
For Person A,
Velocity = 4 m/s
Time = secs
Distance =
From,
Then,
...... (1)
For Person B
Velocity = 5 m/s
Time = (t + 3) secs
Distance =
Also, from
...... (2)
Recall that, +
= 300m
Then, = 300m -
We can then write that,
300m -
Then,
..... (3)
Equating equations (1) and (3), we get
This is the time spent by Person A
Hence, it takes takes them 31.67 secs to meet after Person A starts walking OR
34.67 secs after Person B starts walking
Answer:
D. 0.53
Step-by-step explanation:
