Mathematics
Assertion: When x and y are in indirect proportion, then (x + 1) and (y + 1) are also in indirect proportion.
Reason: Two quantities x and y are said to be in indirect proportion, if xy = k, where k is a constant.
- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- Assertion (A) is true but Reason (R) is false.
- Assertion (A) is false but Reason (R) is true.
Unitary Method
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Answer
Assertion (A) is false but Reason (R) is true.
Explanation
Let's test Assertion with numbers. If x = 2 and y = 6 (where xy = 12) and then x = 3 and y = 4 (where xy = 12), they are in indirect proportion.
Now add 1: (2+1) = 3 and (6+1) = 7. Here, 3 x 7 = 21.
Next set: (3+1) = 4 and (4+1) = 5. Here, 4 x 5 = 20.
Since 21 ≠ 20, the product is not constant. Therefore, (x+1) and (y+1) are not in indirect proportion. Assertion is False.
Hence, option 4 is the correct option.
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Related Questions
Fill in the blanks :
(i) If 6 pens cost ₹ 69, then the cost of 16 pens is …………… .
(ii) If 1 dozen eggs cost ₹ 54, then a tray of 30 eggs will cost …………… .
(iii) A worker is paid ₹ 1610 as wages for 14 days. His wages for 30 days will be …………… .
(iv) 25 boxes of 12 ice-cream cups each, cost ₹ 10500. The cost of 15 boxes of 20 ice-cream cups each, will be …………… .
Writer true (T) or false (F) :
(i) 12 kg apples for ₹ 2160 is a better buy than 15 kg apples for ₹ 2850.
(ii) If 7 men can finish a work in 84 days, then 12 men can finish the same work in 96 days.
(iii) If 9 notebooks cost ₹ 315, then the cost of 20 notebooks is ₹ 700.
(iv) In an indirect proportion, a decrease in one quantity causes an increase in the other quantity.
Rajan runs a typing company that processes the manuscript obtained from publishing companies. There are two processes in his work - typing and typesetting. He owns a team each for the two processes. He received a manuscript from a publishing company RBC. He knows that his team of 25 typists can type 225 pages in a day. Also, his team of 7 typesetters can typeset 90 pages in 5 days.
(1) If the manuscript from RBC needs 1350 pages to be typed, how many days will Rajan's team take to type it ?
- 5
- 6
- 7
- 9
(2) If Rajan employs 5 more typists in his team, in how many days can the work of RBC be completed ?
- 4
- 5
- 6
- 8
(3) In how many days will Rajan’s team of typesetters typeset the work from RBC ?
- 50
- 60
- 75
- 85
(4) If typesetting work begins only after the typing work is finished, what is the least number of days Rajan needs to get the work from RBC done by his existing team of 30 typists and 7 typesetters ?
- 75
- 80
- 81
- 85
Assertion: When the speed is kept fixed, time and distance are in direct proportion.
Reason: Two quantities are said to be in direct proportion if the increase (decrease) in one quantity causes the increase (decrease) in the other quantity.
- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- Assertion (A) is true but Reason (R) is false.
- Assertion (A) is false but Reason (R) is true.