Comment with your working steps and answers.

1. Amy, Brenda and Carrie shared a bag of 31 coins with a total value of $12.20. The bag only contained 20-cent coins and 50-cent coins. Amy received only 20-cent coins. Brenda received 3 more coins than Amy and Brenda’s 3 extra coins added up to 90 cents. Carrie received 7 more coins than Brenda and Carrie’s 7 extra coins added up to $2.60. How much money did Carrie receive?

2. Ms Ho numbered thirty pupils by writing 1, 2, 3, … , 28, 29 and 30 on their name tags.

(a) How many digits did she write in all?

(b) She arranged all the thirty pupils to stand in a row, starting from Number 1 to Number 30. Next, for every second pupil, she asked each pupil to sit. Then, for every third pupil, she asked each standing pupil to sit and each sitting pupil to stand. She followed the same pattern (which is to ask each standing pupil to sit and each sitting pupil to stand) for every fourth pupil, every fifth pupil, and so on till the 30th pupil. How many pupils were standing after the whole process was completed?

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