A new book sold 15 copies at the bookstore on Wednesday. On Thursday the book sold three times that many copies. On Friday the book sold one-fifth the number of copies it did on Thursday. How many copies of the book did the bookstore sell by Friday?
Китоби нав дар китобфурӯшӣ дар чоршанбе 15 нусха фурӯхта шуд. Дар панҷшанбе китоб се маротиба бештар аз ин миқдор фурӯхта шуд. Дар ҷумъа китоб як панҷум аз шумораи нусхаҳое, ки дар панҷшанбе фурӯхта буд, фурӯхта шуд. То ҷумъа китобфурӯшӣ чанд нусхаи китоб фурӯхт?
How many books were sold on Thursday? ** On Thursday 15*3=<<15*3=45>>45 books were sold.
How many books were sold on Friday? ** On Friday 45/5=<<45/5=9>>9 books were sold
How many books were sold by Friday? ** Adding up all three days 15+45+9=<<15+45+9=69>>69 books were sold by Friday
#### 69
How many books were sold on Thursday? ** On Thursday 15*3=<<15*3=45>>45 китоб фурӯхта шуд.  
How many books were sold on Friday? ** On Friday 45/5=<<45/5=9>>9 китоб фурӯхта шуд.  
How many books were sold by Friday? ** Adding up all three days 15+45+9=<<15+45+9=69>>69 китоб то ҷумъа фурӯхта шуд.  
#### 69