MATHEMATICS THE PASSAGE.

48. a. First you find out how long the entire hike canage. Jerry (J) and his grandfather (G) have abe, based on the rate at which the hikers are

2

sum of ages of 110 years. Therefore,J+ G= 110.

5

3

using their supplies; =

1

x

, where 1 is the totalJerry was

1

3

as young as his grandfather 15 yearsamount of supplies and xis the number of daysago. Therefore,J– 15 =

1

3

(G– 15). Either equa-for the whole hike. Cross-multiplying, you get tion can be solved for Jor Gand substituted into(5)

, or 7

1

the other;J= 110 – G; 110 – G– 15 =

1

3

(G– 5);2

days for the2

5

x = 3, so that x =

(3)

4

100 =

3

length of the entire hike. This means that the

G

;G= 75.