Площадь зала 45 кв.м. Чему равны его длина и ширина, если длина на 4м больше ширины?

раскройте скобки употребляя глаголы в past simple и past perfect
1. By two o'clock the teacher (to examine) all the students. 2. On my way to school I (to remember) that I (to leave) my report at home. 3. All my friend; (to be) glad to hear that I (to pass) all the examinations successfully. 4. Poor Oliver (to lie) unconscious on the spot where Sikes (to leave) him. 5. He (to open) his eyes, (to look) around and (to try) to remember what (to happen) to him. 6. All the passengers (to see) at once that the old man (to travel) a great deal in his life. 7. By the time we (to come) to see him, he (to return) home. 8. During the holidays my friend (to visit) the village where he (to live) in his childhood. 9. When they (to enter) the hall, the performance already (to begin). 10. When I came home, my mother (to tell) me that she (to receive) a letter from grandfather. 11. Where you (to work) before you (to enter) the institute? 12. He (to study) French before he (to enter) the university. 13. Lanny (to say) that he (to get) his education in Cape Town. 14. The boy (to want) to act the main part in the play because he (to organize) the theatre. 15. Lanny (not to know) who (to attack) him in the darkness. 16. The girl (to be) glad that she (to find) a seat near the window. 17. Suddenly he (to remember) that he (not to ring) her up in the morning. 18. By the time the train (to reach) the city, he (to make) friends with many passengers. 19. When my uncle (to leave), he (to hurry) to the station to book a ticket. 20. She (to think) that Gert and Lanny (to quarrel).

15 3/28-5 19/28 =  ?Помогите пожалуйста)

В первом киоске на 30 дес. воздушных шаров больше, чем во втором,и на 10 дес. меньше,чем в третьем. На сколько десятков шаров больше в третьем киоске, чем во втором?