Pranali and Prasad started walking to the East and to the North respectively,from the same point and at the same speed. After 2 hours distance between them was 15√2 km. Find their speed per hour.
Answers
When you draw the diagram ,
it will form a right angled triangle in which the hypotenuse is 15√2 km
So use Pythagoras theorem
if they have same speed then after the same no of hour they would have cover the same distance so take perpendicular=base in your right triangle and solve you will get
Pranali and prasad both have covered the same distance of 15 km in 2 hours
hence the answer will be 7.5km/hr
Answer:
Speed of Pranali and Prasad was 7.5 km/hr.
Step-by-step-explanation:
NOTE: Refer to the attachment for the diagram.
In figure,
Point A represents the starting point of Pranali and Prasad.
Seg AB represents the path travelled by Pranali.
Seg AC represents the path travelled by Prasad.
After 2 hours, Pranali reaches point B.
And Prasad reaches point C.
The distance between two points B and C is 15 √2 km.
∴ BC = 15 √2 km
We have given that,
Speed of Pranali and Prasad was same.
Let their speed by x km/hr.
We know that,
Distance = Speed × Time
⇒ Distance AB = x * 2
⇒ AB = 2x km
Also,
Distance AC = x * 2
⇒ AC = 2x km
Now,
In right angled triangle CAB,
∴ BC² = AC² + AB² - - [ Pythagors theorem ]
⇒ ( 15 √2 )² = ( 2x )² + ( 2x )²
⇒ 225 × 2 = 4x² + 4x²
⇒ 8x² = 225 × 2
⇒ x² = 225 × 2 ÷ 8
⇒ x² = 225 × 1 ÷ 4
⇒ x² = 225 / 4
⇒ x = 15 / 2 - - [ Taking square roots ]
⇒ x = 7.5
∴ Speed of Pranali and Prasad was 7.5 km/hr.
