Direct and inverse proportion: Direct and inverse proportion Presented by: Mohammed Mutahar Mujahid
Direct proportion: Direct proportion When we talk about a direct proportion, we are talking about a relationship where as x increases, y increases or x decreases, y decreases a constant rate. By: Mohammed Mutahar Mujahid
Some examples of direct proportion: Some examples of direct proportion 1. If the cost of 1 gel pen is Rs.10, then what will be the cost of 5 such gel pens? Ans. Rs.50 Here as number of pens increased from 1 to 5, the cost of pens is also increased from 10 to 50. By: Mohammed Mutahar Mujahid
PowerPoint Presentation: 2. If the weight of 1 mathematics book is 500 grams, what will be the weight of 8 such books? Ans. 4000 grams Here the number of books increased from 1 to 8, the weight of 8 books also increased from 500 grams to 4000 grams. By: Mohammed Mutahar Mujahid
Formulae used in direct proportion : Formulae used in direct proportion Quantity X1 X2 Cost Y1 Y2 By: Mohammed Mutahar Mujahid
Inverse proportion : Inverse proportion Inverse is totally opposite to direct. In an inverse proportion as one goes up and other goes down in same ratio. By: Mohammed Mutahar Mujahid
Some examples of inverse proportion: Some examples of inverse proportion 1. If 5 workers for 48 hours then 10 workers will work in how many hours? Ans. 24 hours Here as the number of workers increase from 5 to 10, the number of hours decrease form 48 to 2 hours. By: Mohammed Mutahar Mujahid
PowerPoint Presentation: 2. A car moving with a speed of 40 km/hr covers a fix distance in 10 minutes. If speed of car increased to 80 km/hr then how much does it covers in same distance? Ans. 5 minutes Here the speed is increased from 40 to 80 km/hr, the time decreased from 10 to 5 minutes By: Mohammed Mutahar Mujahid
Formulae in inverse proportion : Formulae in inverse proportion Speed in km/hr 3 5 6 15 Time taken in min. 30 18 15 6 By: Mohammed Mutahar Mujahid
Recapitulation: Recapitulation 1. With direct proportion we divide or x’s and y’s 2. In inverse proportion we multiply them. By: Mohammed Mutahar Mujahid
End of presentation: End of presentation By: Mohammed Mutahar Mujahid