Question

3 roads,a,b,and c .B is 3 times the longer than a.C is twice as long as b.What fraction of the total length of the roads is the length of a.If road b is 7 miles longer than a, what is the total length of c.

Answer 1

Answer:

(a) $\dfrac{1}{10}$

(b) 21 miles

Step-by-step explanation:

(a) From the question,

b = 3a

c = 2b = 2 × 3a = 6a

The total length of the road = a + b + c = a + 3a + 6a = 10a

The fraction of the total length of the roads that is a

= $\dfrac{a}{a+b+c} = \dfrac{a}{10a} = \dfrac{1}{10}$

(b) If b is 7 miles longer than a, then

b - a = 7

3a - a = 7

2a = 7

a = 3.5

c = 6a = 6 × 3.5 = 21 miles