David has two younger sisters, jane and sally. jane is 2 years older than sally and david is 4 times older than jane. sally is z years old.

part a

write two equivalent expressions that represent david’s age in terms of sally’s age, z, and explain how the two expressions relate to one another.

part b

which expression is more useful? why?

2+z(4) and 4z+2

Step-by-step explanation:

The first one is more useful because it has everything in order. How much Jane is older than Sally then, how many times David is older than Jane.

(Hope it's right.)

three-fourths of an hour

36÷48=0.75

0.75=

the total estimated nappy use.=10,500,000

step-by-step explanation:

given that on an average the average baby uses 3528 napkins.

in a particular year 2014, the number of births were 299697 in new south wales.

rounding off the number of births to the nearest hundred thousand we have

no of birtsh = 300000

also rounding off the average usage to nearst thousand we get

average use of a baby = 3500

hence total number of nappy estimated to be used = 3500x300000

= 10,500,000

answer is 10,500,000 nappies