42|2
21|3
7|7
1
The combination is <span>237.</span>
1. C
2. A
Hope this helped, enjoy your day.
Answer:
17.2°
Explanations
To find angle A, use the cosine rule.
a^2 = b^2 + c^2 - 2 × a × c cos A
4^2 = 7^2 + 10^2 - 2 × 7 × 10 cos A
16 = 49+ 100 - 140 × cosA
16 = 149 - 140cosA
16- 149 = - 140cosA
-133 = - 140cosA
cosA = 133/140
cosA = 0.95
A = 17.2°
Answer: 81.85 km/hr
Converting m/sec into km/hr, 25 m/sec = 90 km/hr
Average =
Time = 50/90 = 5/9 hr
next 120 km at an average speed of 80km/h
=> Time = 120/80 = 3/2 hr
last part of its journey at an average speed of 90km/h in 35 Minutes
time = 35 minutes = 35/60 hr = 7/12 hr
Distance covered = 90 * 7 /12 = 105/2 km
Total Distance = 50 + 120 + 105/2 = 435/2 km
Total time = 5/9 + 3/2 + 7/12 = ( 20 + 54 + 21) /36 = 95/36
Average speed = (435/2)/(95 /36) = 432 * 18 /95 = 81.85 km/hr
