If Matilda earns $48 in 4 hours, then she must earn 48/4 (12) dollars per hour. We know she earns $12 per hour, and that she made $288, so we divide the total amount earned (288) by her hourly wage ($12) to find she worked 288/12 or 24 hours.
The answer is D. 200m = 2cm. That's because to get from meters to centimeters, you need to multiply by 100. 200 * 100 is not 2, therefore D is the answer.