Hey <drstevewu>,

Appreciate it will be helpful if answer keys are also provided. Thank you.

Following are my worked solutions :

Q1.

(a)

80 minutes = 1 hr 20 min

1 hr 20 min from 12 pm is **1.20pm**

(b)

Let the equal number of bottle caps be 1u.

<In 1 minute>

A: (1u / 80) bottle caps

B: (1u / 120) bottle caps

Given that Machine A produced 5 more bottle caps per minute than Machine B, we have ...

(1u / 80) - (1u / 120) = 5

(3u / 240) - (2u / 240) = 5

1u --> 5 × 240 = 1200

1200 --> 80 mins

3000 --> (80 / 1200) × 3000 = **200 mins ( 3 hrs 20 mins )**

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Q2.

Total score for 80 singers = 58.5 × 80 = 4680

Apply <Assumption> method, we have ...

Total score for 80 female singers = 64 × 80 = 5120

5120 - 4680 = 440

64 - 56 = 8

440 ÷ 8 = 55

There were **55** male singers.

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Trust these help.

Do let me know again if there are further clarifications or if these are different from the <Anskey>.

Cheers,

Edward