1. Express the given ratio in lowest term: i) 285 to 145 ii) 230 to 140 iii) The ratio of 15 days to a month is ……………….. iv) The ratio of 9 m to 27 cm is ……………. v) The ratio of 2 km to 500 m is ………………… 2. If 6 movie tickets cost ₹ 1800. Find the cost of 17 movie tickets…………… 3. a) 20% of a number is 11 ……………… b) 21 1/4 % of a number is 51 ……………. 4. If angles of a triangle are in the ratio 4:3:2, then the value of largest angle is …………. 5. Change the given fractions to per cent………………a) 2 2/5 b) 12/25 6. Find the cost price of a table, if selling the table for ₹ 535, shopkeeper gains 7%. 7. Find the monthly salary of Rachana, if she saves ₹ 2500 and her savings are 10% of her salary.
Answers
I1 = Current flowing through the outer circuit
I2 = Current flowing through branch AB
I3 = Current flowing through branch AD
I2 - I4 = Current flowing through branch BC
I3 + I4 = Current flowing through branch CD
I4 = Current flowing through branch BD
For the closed circuit ABDA, potential is zero i.e.,
10I2 + 5I4 - 5I3 = 0
2I2 + I4 - I3 = 0
I3 = 2I2 + I4 … (1)
For the closed circuit BCDB, potential is zero i.e.,
5(I2 - I4) - 10(I3 +I4) - 5I4 = 0
5I2 + 5I4 - 10I3 - 10I4 - 5I4 = 0
5I2 - 10I3 - 20I4 = 0
I2 = 2I3 + 4I4 … (2)
For the closed circuit ABCFEA, potential is zero i.e.,
- 10 + 10 (I1) + 10(I2) + 5(I2 - I4) = 0
10 = 15I2 + 10I1 - 5I4
3I2 + 2I1 - I4 = 2 … (3)
From equations (1) and (2), we obtain
I3 = 2(2I3 + 4I4) + I4
I3 = 4I3 + 8I4 + I4
- 3I3 = 9I4
- 3I4 = + I3 … (4)
Putting equation (4) in equation (1), we obtain
I3 = 2I2 + I4
- 4I4 = 2I2
I2 = - 2I4 … (5)
It is evident from the given figure that,
I1 = I3 + I2 … (6)
Putting equation (6) in equation (1), we obtain
3I2 +2(I3 + I2) - I4 = 2
5I2 + 2I3 - I4 = 2 … (7)
Putting equations (4) and (5) in equation (7), we obtain
5( - 2 I4) + 2( - 3 I4) - I4 = 2
- 10I4 - 6I4 - I4 = 2
17I4 = - 2.
Equation (4) reduces to
I3 = - 3(I4)
Total current = 10/17 A