Question

A person takes a trip, driving with a constant speed of 97.5 km/h, except for a 24.0-min rest stop. The person's average speed is 74.2 km/h. (a) How much time is spent on the trip? h (b) How far does the person travel? km

Answer 1

Sol ca) Average Apeed sped Time of rest Ahop ts 74.2 km/A 97-5 km /h Com tant 24.0 min o.4 h. We know V T T= dis total di tance covured by the person Constant Apeed Here 1 at Vt is time taken 97-5 Km/h x ナ Thanfone Total time 4 van by T: ナ+ナms t+ tns ++ tas Vxt V

Puting the values o1 v, and ts 97-5 O.4 97.5 O.4 74-2 97-5 74.2 1.27 hour Therdfore total time taken s T- t tm 1.27 04 T ML9.1 olvxt (4) d 97.5 x 1.27 km. 12 3. 82 11 This i the nguied

Answer 2

SOLUTION :

a.

Let time of travel be t hr and distance covered be d km.

Rest time = 24 min = 24/60 - 0.4 hr.

So, 

d = 97.5 * (t - 0.4) 

Also, d = 74.2 * t

So,

97.5 (t - 0.4) = 74.2 t

=> 97.5 t - 39 = 74.2 t

=> 97.5 t - 74.2 t = 39

=> 23.3 t = 39

=> t = 39 / 23.3 = 1.6738 hr = 1 hr 40 min 26 sec approx. (ANSWER).

b.

d = 74.2 * 1.6738 = 124.20 km approx. (ANSWER).