After reading 7/9 of a book , 40 pages are left .How many pages are there in the book

180 pages

Step-by-step explanation:

Let the equation be

x - 7/9x = 40

9x - 7x = 360

x = 360 / 2 = 180

The book has total 180 pages

Means he has read (180 - 40) = 140 pages

21/58.

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answer: bea's uncle is 25 years old.

step-by-step explanation:

given the equation , we can say that the variable "x" represents the age of bea's uncle. then to find his age, we need to solve for "x":

we must add 15 to both sides of the equation:

now we need to divide both sides of the equation by 3:

therefore, we can conclude that bea's uncle is 25 years old.