How do we know when to use a histogram and when to use a a bar graph.

FRIEND,
IT WILL BE GIVEN IN THE QUESTION WHETHER WE SHOULD DRAW HISTOGRAM OR BAR GRAPH.

REGARDS

sne

Histogram is used when there is a continous data.Bar charts can be used for many other datas

usually, it will be mentioned in the question itself. you dont need to worry. just study how to make a histogram and a bar graph.
all the best. 
regards
 

it is given in the question