A number was written on the board. One student increased the number by 23, but another student decreased the number by 1. The first student’s result was 7 times greater than the result of the second student. What is the number written on the board?

5

Step-by-step explanation:

let the number written on the board be x.

1st student's number= x +23

2nd student's number= x -1

1st student's number= 7(that of the 2nd student),

x +23= 7(x -1)

x +23= 7x -7 (expand)

7x -x= 23 +7 (bring constant to 1 side)

6x= 30 (simplify)

x= 30 ÷6 (÷6 on both sides)

x= 5

Thus, the number written on the board is 5.

a

b

d

step-by-step explanation:

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