✔ 最佳答案
Johnny drives a motorcycle at 120km/hr for 30 minutes and then 90km/hr for 1 hour. His average speed for the whole journey is
The answer is b.
Distance = Speed x Time
Total distance
= (120 km/hr) x (30 min) + (90 km/hr) x (1 hr)
= (120 km/hr) x (0.5 h) + (90 km/hr) x (1 hr)
= (60 km) + (90 km)
= 150 km
Total time
= (30 min) + (1 hr)
= (0.5 hr) + (1 hr)
= 1.5 hr
Average speed
= (Total distance)/(Total time)
= (150 km)/(1.5 hr)
= 100 km/hr
=====
Frederick is making a model of the Central Plaza. He uses a scale of 4cm to 20m. If the actual height of the Central Plaza is 374m, find the height of the model.
The answer is c.
Let h cm the height of the model.
(4 cm) : (20 m) = (y cm) : (374 m)
4/20 = y/374
20y = 4(374)
20y = 1496
y = 74.8
Hence, the height of the model is 74.8 cm
=
