Question

Mark uses his calculator for 80% of his maths homework

questions. Twelve questions are answered with his calculate
How many questions does Mark have for homework​

Answer 1

The number of questions in Mark's homework is:

• 60 questions.

Explanation:

To identify the number of questions of the homework, first, you must identify the percentage that is the 12 question Mark calculates by himself: if in 80% he uses calculator, in 20% he doesn't, I mean, he uses his own calculates, by this reason:

• 20% = 12 questions of the homework.

With this data, we can use a simple rule of three and find the number of question that correspond to 80%.

If:

• 20% = 12 questions
• 80% = x

Then:

• 
  `x=(80*12)/(20)` (you can use the percentage if you want, the result is the same)
• 
  `x=(960)/(20)`
• 
  `x=48`

At last, we add the 80% and the 20% of the questions:

• Total of questions = 80% with calculator + 20% with his calculates
• Total of questions = 48 questions + 12 questions
• Total of questions = 60 questions

As you can see, the number of questions in Mark's homework is 60 questions.