University:
High School
Course:
High School Mathematics
Academic year:

2023
Views:

158

Pages:

5
Author:

anon

Hwk: Pg. 226: #3. Let x represent Jamal`s score. Fayth`s score: x+200 Jamal`s score + Fayth`s score = 2250 𝑋 + 𝑥 + 200 = 2250 2𝑥 + 200 = 2250 2𝑥 = 2050 2𝑥 2 = 2050 2 𝑋 = 1025 Jamal earned 1025 points and Fayth earned 1225 points Let x represent Natalie`s goals 𝑋 + 8 ← Chantal`s goals 2𝑥 ← Samara`s goals X+x+8+2x=52 4x+8=52 4x=52-8 4x=44 X=11 Chantal`s=x+8 =11+8 =19 Samara`s =2x = 2 ×11 =22 Natalie scored 11 goals, Chantal`s scored 19 goals and Samara scored 22 goals Applications of Percent The word "percent" means per hundred Example 1: a) Calculate 16% of 85 16% of 85 = 0. 16 ×85 =13.6 b) 18% of what number is 50? Let x represent a number 18% of x =50 0. 18𝑥 = 50 0.18𝑥 0.18 = 50 0.18 𝑋 = 277. 78 c) What percent of 65 is 0.13? 𝑥(65) = 0. 13 65𝑥 = 0. 13 65𝑥 65 = 0.13 65 𝑋 = 0. 002 𝑋 = 0. 2% Example 2: The price of an 8 GB iPod touch is $111.99 after a 44% discou nt. What was the original price of the iPod touch? Solution: 100%-44%=56% So, the iPod touch is worth 56% of the original price. Let x rep. the original price of the iPod touch, they 56% of x = 111.99 0.56x=111.99 0.56𝑥 0.56 = 111.99 0.56 x=199.98 The original price of the iPod touch was $199.98. Example 3: A fertilizer contains nitrogen, phosphorus, and potassium in th e ratio 35:20:14 by mass. This means that 35% is nitrogen, 20% is phosphorus, and 14% potassium. Calculate the mass of each element in a 10‐kg bag of fertilizer. Solution: 35%+20%+14%=69% So, 69% of the bag is nitrogen, phosphorus and potassium. 69% of 10=0. 69 ×10 =6.9 So, 6.9 kg of the bag is nitrogen, phosphorus and potassium. (3.1 kg is a fill) OR 35% of 10 = 0. 35 × 10 =3.5 20% of 10 =0. 20 × 10 =2 14% of 10 = 0. 14 × 10 =1.4 35% 69 % ×6. 9 = 3. 5 20% 69% ×6. 9 = 2 14 % 69 % ×6. 9 = 1. 4 The bag contains 3.5 kg of nitrogen, 2 kg of phosphorus and 1.4 kg of potassium Example 4: Based on current cancer rates, 19 out of 50 Canadian women will develop cancer during their lifetime and 43 out of 100 Canadian men will develop cancer d uring their lifetime. Predict how many women out of 700 are likely to develop cancer. Solution: Percent of women = 19/50 =38/100 =38% So, 38% of Canadian women will cancer 38% of 700 =0. 38×700 =266 266 Canadian women are likely to develop cancer Example 5: Seven out ten people prefer coffee over tea. How many woul d prefer coffee over tea in a group of 130 people? Solution: 7 10 = 70 100 =70% So, 70% of people prefer coffee over tea 70% of 130 = 0. 70 × 130 =91 91 people out of 130 people prefer coffee over tea