In a certain year, Kwaku paid for electricity consumed each month as follows, the cost of the first 30 units was 10p per unit; the cost of the next 30 units was 7p per unit; the cost of each additional unit is 5p. (i) If Kwaku used 420 units of electricity in July that year, calculate the amount
he paid.
(ii) If Kwaku paid ¢27.10 in August last year, calculate the number of units of
electricity he used.
(iii) Find, correct to two decimal places, the percentage change in Kwaku‟s
consumption of electricity from July to August that year

If benito is selecting samples of five values from the table, which row will result in the greatest mean? population data row 1 4 2 2 3 3 row 2 3 3 4 3 2 row 3 2 4 3 4 3 row 4 3 4 4 7 3 row 1 row 2 r

Each of the following data sets has a mean of x = 10. (i) 8 9 10 11 12 (ii) 7 9 10 11 13 (iii) 7 8 10 12 13 (a) without doing any computations, order the data sets according to increasing value of standard deviations. (i), (iii), (ii) (ii), (i), (iii) (iii), (i), (ii) (iii), (ii), (i) (i), (ii), (iii) (ii), (iii), (i) (b) why do you expect the difference in standard deviations between data sets (i) and (ii) to be greater than the difference in standard deviations between data sets (ii) and (iii)? hint: consider how much the data in the respective sets differ from the mean. the data change between data sets (i) and (ii) increased the squared difference îł(x - x)2 by more than data sets (ii) and (iii). the data change between data sets (ii) and (iii) increased the squared difference îł(x - x)2 by more than data sets (i) and (ii). the data change between data sets (i) and (ii) decreased the squared difference îł(x - x)2 by more than data sets (ii) and (iii). none of the above

When a whole number is multiplied by 104, how does the placement of the decimal point change? a. it moves ten places to the right. b. it moves four places to the left. c. it moves ten places to the left. d. it moves four places to the right.