A man travels a distance of 196km by train and return in carwhich travel at a speed of 21kmper hour faster than train,if the total journey takes 11hours find the average speed of train and car respectively.?
Answers
Step-by-step explanation:
Let the speed of train be x km / hour
Speed of car = (x+21) km/ hour
196 / x + 196 / (x+21) = 11
MULTIPLY BOTH SIDES BY x ( x+21)
196 ( x+21) + 196x = 11x^2 + 231x
196x + 4116 + 196x = 11x^2 +231x
11x^2 -161x - 4116 = 0
11x^2 -308x +147x - 4116 = 0
11x ( x - 28) + 147 ( x -28 ) = 0
( 11x +147) ( x-28) = 0
Rejecting the negative value of x
x = 28
ANSWER Train = 28 km/ hour Car = 49 km/ hour
CHECK
196 /28 = 7 hours
196/49 = 4 hours
ADD = 11 hours
Answer:
average speed of train= 28 km per hour
average speed of car = 49 km per hour
Step-by-step explanation:
Let the speed of train be x
Let the speed of car is equal to x + 21
196 / x +196/ x + 21 = 11
multiply by x x + 21
196 into x +21 + 196 x =11x^2+231
so 196 x + 4116 +196x =11 x ^2+231
11x^2 - 4 x 61 x -4116=0
11 x^2 -308 x + 147 x - 4860 =0
11 x (x - 48) +147 (x-28) =0
(11 x + 147) = 0
therefore x = 1471
x =28
therefore average speed of train is 28 km per hour
and the average speed of car =28 + 21 = 49 km per hour