Advertisements
Advertisements
प्रश्न
Solve 0.4x + 0.3y = 1.7; 0.7 x − 0.2y = 0.8
उत्तर
0.4x + 0.3y = 1.7
∴ 4x + 3y = 17 ......(i)[Multiplying both sides by 10]
0.7x – 0.2y = 0.8
∴ 7x – 2y = 8 ......(ii)[Multiplying both sides by 10]
Multiplying equation (i) by 2, we get
8x + 6y = 34 ......(iii)
Multiplying equation (ii) by 3, we get
21x – 6y = 24 ......(iv)
Adding equations (iii) and (iv), we get
8x + 6y = 34
+21x – 6y = 24
29x = 58
∴ x = `58/29` = 2
Substituting x = 2 in equation (i), we get
4(2) + 3y = 17
∴ 8 + 3y = 17
∴ 3y = 9
∴ y = `9/3` = 3
∴ x = 2 and y = 3 is the solution of the equation 0.4x + 0.3y = 1.7 and 0.7x – 0.2y = 0.8.
APPEARS IN
संबंधित प्रश्न
Solve the following system of equations by cross-multiplication method.
ax + by = a – b; bx – ay = a + b
Solve the following system of equations by cross-multiplication method x + y = a – b; ax – by = a2 + b2
Solve the following system of equations in x and y by cross-multiplication method
`(a – b) x + (a + b) y = a^2 – 2ab – b^2`
`(a + b) (x + y) = a^2 + b^2`
Form the pair of linear equations in the following problems and find their solutions (if they exist) by any algebraic method :
A part of monthly hostel charges is fixed and the remaining depends on the number of days one has taken food in the mess. When a student A takes food for 20 days she has to pay Rs 1000 as hostel charges whereas a student B, who takes food for 26 days, pays Rs 1180 as hostel charges. Find the fixed charges and the cost of food per day.
Solve each of the following systems of equations by the method of cross-multiplication :
x + 2y + 1 = 0
2x − 3y − 12 = 0
Solve each of the following systems of equations by the method of cross-multiplication
2x − y = 6
x − y = 2
Solve each of the following systems of equations by the method of cross-multiplication
`(x + y)/(xy) = 2`
`(x - y)/(xy) = 6`
Solve each of the following systems of equations by the method of cross-multiplication :
`ax + by = (a + b)/2`
3x + 5y = 4
Solve each of the following systems of equations by the method of cross-multiplication :
mx – my = m2 + n2
x + y = 2m
Solve the system of equations by using the method of cross multiplication:
3x + 2y + 25 = 0, 2x + y + 10 = 0
Solve the system of equations by using the method of cross multiplication:
2x + y – 35 = 0,
3x + 4y – 65 = 0
Solve the system of equations by using the method of cross multiplication:
7x - 2y – 3 = 0,
`11x - 3/2 y – 8 = 0.`
Solve the system of equations by using the method of cross multiplication:
`x/6 + y/15 – 4 = 0, x/3 - y/12 – 19/4 = 0`
If `|( 4,5), (m , 3)|` = 22, then find the value of m.
A father's age is three times the sum of the ages of his two children. After 5 years his age will be two times the sum of their ages. Find the present age of the father.
Ankita travels 14 km to her home partly by rickshaw and partly by bus. She takes half an hour if she travels 2 km by rickshaw, and the remaining distance by bus. On the other hand, if she travels 4 km by rickshaw and the remaining distance by bus, she takes 9 minutes longer. Find the speed of the rickshaw and of the bus.
A two-digit number is obtained by either multiplying the sum of the digits by 8 and then subtracting 5 or by multiplying the difference of the digits by 16 and then adding 3. Find the number.
Anuj had some chocolates, and he divided them into two lots A and B. He sold the first lot at the rate of ₹ 2 for 3 chocolates and the second lot at the rate of ₹ 1 per chocolate, and got a total of ₹ 400. If he had sold the first lot at the rate of ₹ 1 per chocolate, and the second lot at the rate of ₹4 for 5 chocolates, his total collection would have been ₹460. Find the total number of chocolates he had.
