Solution :
The term 'literacy rate' provides the ability of a person who is from a definite age group can read or write.
a). 
does not determine the rate at which the variable explains another, but it explains the amount the amount of variability in one of the variables as explained by the other variable.
b). The slope given provides an expected improvement but it cannot guarantee the improvement. The value may be less or it could be more also.
The regression model provides the prediction and not the actual values.
There's two ways to do this.
The first way:
Work out the amount of sugar needed to make one cake, and then multiply that by 7.
30 grams ÷ 4 cakes = 7.5 grams for 1 cake.
7.5 grams × 7 cakes = 52.5 grams for 7 cakes.
The second way:
Work out the ratio of sugar:cake by doing 7 ÷ 4, and then multiplying that value by 30.
7 cakes ÷ 4 cakes = 1.75
1.75 × 30 grams = 52.5 grams for 7 cakes.
Either way, the answer is 52.5 grams.
