Advertisements
Advertisements
Question
Complite the following table given that x varies directly as y .
| x | 2.5 | ... | ... | 15 |
| y | 5 | 8 | 12 | ... |
Advertisements
Solution
\[\text{ Here, x and y vary directly } . \]
\[ \therefore x = ky\]
\[x = 2 . 5 \text{ and } my = 5\]
\[i . e . , 2 . 5 = k \times 5\]
\[ \Rightarrow k = \frac{2 . 5}{5} = 0 . 5\]
\[\text{ For y = 8 and k = 0 . 5, we have } : \]
\[x = ky\]
\[ \Rightarrow x = 8 \times 0 . 5 = 4\]
\[\text{ For y = 12 and k = 0 . 5, we have: } \]
\[x = ky\]
\[ \Rightarrow x = 12 \times 0 . 5 = 6\]
\[\text{ For x = 15 and k = 0 . 5, we have } : \]
\[x = ky\]
\[ \Rightarrow 15 = 0 . 5 \times y\]
\[ \Rightarrow y = \frac{15}{0 . 5} = 30\]
APPEARS IN
RELATED QUESTIONS
A cistern can be filled by one tap in 8 hours, and by another in 4 hours. How long will it take to fill the cistern if both taps are opened together?
If 7 kg onions cost 140 rupees, how much must we pay for 12 kg onions?
A birthday party is arranged in third floor of a hotel. 120 people take 8 trips in a lift to go to the party hall. If 12 trips were made how many people would have attended the party?
A postman can sort out 738 letters in 6 hours. How many letters can be sorted in 9 hours?
Both x and y vary directly with each other and when x is 10, y is 14, which of the following is not a possible pair of corresponding values of x and y?
It is given that l varies directly as m. Find l, when m is 33.
From the following table, determine if x and y are in direct proportion or not.
| x | 4 | 7 | 10 | 16 |
| y | 24 | 42 | 60 | 96 |
30 persons can reap a field in 17 days. How many more persons should be engaged to reap the same field in 10 days?
Match each of the entries in Column I with the appropriate entry in Column II
| Column I | Column II |
| 1. x and y vary inversely to each other | A. `x/y` = Constant |
| 2. Mathematical representation of inverse variation of quantities p and q |
B. y will increase in proportion |
| 3. Mathematical representation of direct variation of quantities m and n |
C. xy = Constant |
| 4. When x = 5, y = 2.5 and when y = 5, x = 10 | D. `p oo 1/q` |
| 5. When x = 10, y = 5 and when x = 20, y = 2.5 | E. y will decrease in proportion |
| 6. x and y vary directly with each other | F. x and y are directly proportional |
| 7. If x and y vary inversely then on decreasing x | G. `m oo n` |
| 8. If x and y vary directly then on decreasing x | H. x and y vary inversely |
| I. `p oo q` | |
| J. `m oo 1/n` |
Many schools have a recommended students-teacher ratio as 35:1. Next year, school expects an increase in enrolment by 280 students. How many new teachers will they have to appoint to maintain the students-teacher ratio?
