f.3 maths inequalities

2011-10-30 8:15 am
要steps thx

1. The sum of two consecutive odd no. is greater than 28. Find the least value of the larger odd no.

2. Mr Chan is driving at x km/h. If his speed increases by 15 km/h, the distance travelled in 2 hours will be greater than that of travelling in 3 hours at his original speed. Find the range of the value of y.
更新1:

2. * Find the range of value of x.

回答 (1)

2011-10-30 4:12 pm
✔ 最佳答案
1. Let the larger odd no. be x, the smaller odd no. will be x - 2.
x + (x - 2) > 28
2x - 2 > 28
2x > 30
x > 15
so least value = 17.
2.
Distance travelled in 3 hours at original speed = 3x
Distance travelled in 2 hours at new speed = 2(x + 15)
so 2(x + 15) > 3x
2x + 30 > 3x
30 > x
so x must be less than 30 km/h.


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