hi,

let me start with no. 3 (most interesting):

Qn 3:

area of BEC - white unshaded area = shaded area Y

area of ABCD - white unshaded area = shaded area X

*notice*: there is a common white unshaded area in both cases, which can be removed from the equation.

therefore,

(1/2) x 9 x 7 - (white unshaded) - 13.5 = 9 x AB - (white unshaded)

63 / 2 - 13.5 = 9 x AB

thus,

AB = (31.5 - 13.5) / 9 = 18 / = **2 cm**

Qn 1:

(a) in the second store, she spent $18 more than half of what she had left after spending money in first store.

so this $18 is really half of what's left after spending at first store, right?

so, she spent $18 x 2 = **$36** at second store.

(b) this $36 + $18 = $54 will then be half of all money she had when she entered 1st store.

thus, she had $54 x 2 = **$108 **at first, when she went shopping.

Qn 2:

since motorcyclist went ahead of car by 1.5 hours, he was thus 1.5 h x 60 km/h = 90 km ahead of car at 10 am when car left.

now, car needed to catch up that distance of 90 km.

from 10 am, car is ahead in distance of motorcyclist by (85 - 60) km/h = 25 km/h

therefore, car took 90 km / 25 km/h = 18 / 5 hours to catch up and overtook other at mid-point.

that is to say, car travelled total distance of (18/5) h x 85 km/h = 306 km

and this is at mid-point between two towns.

So, total distance between two towns = 306 km x 2 = **612 km**

Cheerio!