Question

In a mathematics class, 20 children had forgotten
their rulers and 17 had forgotten their pencils, "Go
and borrow them from someone at once", said the
teacher, 24 children left the room, then how many
children had forgotten both is​

Answer 1

Question

In mathematics class, 20 children had forgotten their rulers and 17 had forgotten their pencils, "Go and borrow them from someone at once" said the teacher .24 children's left the room, then how manyn childrens had forgotten both ?

Given

• 20 children's forgotten third rulers
• 17 childrens forgotten their pencils
• 24 children's left the room to borrow then from someone once only.

Required to Find

How many childrens forgotten both rulers and pencils?

Solution

•Let A be the set of childrens that have forgotten their rulers

•Let B be the set of children that have forgotten their pencils

n ( AUB ) = 24

n ( A ) = 20

n ( B ) = 17

n ( A U B ) = n ( A ) - n ( B ) - n (AnB)

= 20 + 17 - 24

= 13

More

Tips for Maths succes

• So all the homework.Don't ever think of homework as a choice
• Analyse and understand every mistake
• Basic skills are essential

Do you know ?

the number 9 is revered in Hinduism and considered a complete perfected and the divine number because it represents the end of a cycle in the decimal system, which originated from the India subcontinent as early as 3000 BC Nine is a significant number in norse mythology!!

Chinese people like nine very much as 9 has a same pronunciation with meaning (Jiu,everlasting) since 9 the highest single digit number in base ten stands for completeness and eternity !!