# IGCSE Mathematics Paper-1: Specimen Questions with Answers 177 - 180 of 324

## Question 177

## Question 178

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Short Answer▾There are 10 boys and 15 girls in a choir.

The probability that Carla arrives at school before 09: 00 is .

What is the probability that Carla does not arrive before 09: 00?

Write your answer as a fraction.

### Explanation

- Here the given probability that Carla arrives at school before 09: 00 is
- And find the probability that Carla does not arrive before 09: 00

## Question 179

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Short Answer▾The figures below are similar. The labelled sides are corresponding. What is the perimeter of the large pentagons?

### Explanation

- Find the ratio of the corresponding side lengths.
- Find the ratio of the perimeters.
- Use these two ratios to set up a proportion and solve for The perimeter of the large pentagon is 50 cm.

## Question 180

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Short Answer▾A website is selling packages of Helium confetti Balloons for Rs. 60, but mentions that they original cost Rs. 80. What is the discount percentage?

### Explanation

The percent of change formula can be used to find percent of discount.

Write the number as a percent.

The percentage of discount is 25%.