Summary
Highlights
Out of 495 grade 6 students, 80% will have their confirmation this year. The question asks how many will NOT have their confirmation. If 80% will, then 20% will not. The calculation is 20% of 495, which is 0.20 * 495 = 99 students.
A book sale sold 215 books, which comprises 87.5% of all their books. The problem asks for the approximate total number of books. The setup is 215 = 0.875 * X. The solution involves isolating X by dividing 215 by 0.875, leading to approximately 245 books after careful division and approximation given the nature of an entrance exam.
Ms. O introduces herself and her background with the Philippine Science High School. She then tackles the first problem, which asks to find the number of students under 10 years old if 1/6 of 126 students meet this criterion. The solution involves dividing 126 by 6, resulting in 21 students.
The second problem involves Mr. Rodriguez planting mango seedlings. He starts with 1235 seedlings and plants 800 in one area and 320 in another. To find out how many are left, the total planted (1120) is subtracted from the initial amount (1235), leaving 115 seedlings.
This problem focuses on proportions, specifically 1/3 is to n as 1/4 is to 6. Ms. O demonstrates how to write this as fractions and use cross-multiplication to solve for 'n'. The steps include simplifying fractions and isolating 'n', leading to an answer of 8.
The fourth problem deals with setting up an equation to find the cost of 12 bananas, given that 5 bananas cost 3 pesos and 75 centavos. The solution involves establishing a proportion: 5 bananas / 3.75 pesos = 12 bananas / X, where X is the unknown cost.
This problem presents a ratio of two numbers as 14 is to 3. If the smaller number is 57, the task is to find the larger number. Ms. O explains how to determine the multiplier (57/3 = 19) and apply it to the larger part of the ratio (14 * 19 = 266).
Given a room of 60 people with a ratio of 3 females for every 2 males, the problem asks for the number of males and females. The method involves adding the ratio parts (3+2=5), dividing the total people by this sum (60/5=12 per part), then multiplying by each ratio part (3*12=36 females, 2*12=24 males).
Three boys can fill a water tank in two hours. The problem asks how long it will take four boys to do the same job. Ms. O uses the concept of work rate (1/rate) and sets up an equation to find the time for four boys. The answer is 1.5 hours.
Mrs. Benitez allocates 105 pesos daily to her three children in the ratio of 4:2:1 (college, high school, grade school). The problem asks for the grade school child's daily allowance. The sum of the ratio parts (4+2+1=7) divides the total allowance (105/7=15 pesos per part). The grade school child receives 1 part, so 15 pesos.