What famous saying does this rebus mean?

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In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

At my favorite fruit stand,
an orange costs 18,
a pineapple costs 27,
and a grape costs 15.
Using the same logic, can you tell how much a mango costs?

All of the flowers I have are orchids except two. All of the flowers I have are hibiscuses except two. All of the flowers I have are roses except two.

Can you tell me how many flowers I have?

How many triangles are there on the puzzle below?

Count the number of triangles in the picture below:

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

What has lots of eyes, but can’t see?

I had an infinite supply of water and 5 litres and 3 litres jars.

How would you measure exactly 4 litres in the least number of steps?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?