Since we know that x3 + y3 + z3 – 3xyz = (x + y + z)( x2 + y2 + z2 – xy – yz - zx)

Using (1) and (2) & x + y + z = 9

⇒ x3 + y3 + z3 – 3xyz = 81 × 9

∴ x3 + y3 + z3 – 3xyz = 729


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Q1. The difference of two numbers is 5 và the difference of their squares is 105. Find the average of these numbers.

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Q2. The value of(frac3.57 imes 3.57 imes 3.57 - 1.23 imes 1.23 imes 1.233.57 imes 3.57 + 3.57 imes 1.23 + 1.23 imes 1.23)+ 2.56 will be:
Q5. If a + b - c = 0, then hat is the value of(frac(b-c)^24bcfrac(c-a)^24cafrac(a+b)^24ab?)
Q1. There were 120 students who went for summer camp. đôi mươi students joind them after some time, Due to lớn which the cost of consumption increased by Rs. 80 per day & the average cost of each students decrease by Rs. 5. Find the initial consumption of each student.
Q2. The difference of two numbers is 5 và the difference of their squares is 105. Find the average of these numbers.
Q3. The value of(frac3.57 imes 3.57 imes 3.57 - 1.23 imes 1.23 imes 1.233.57 imes 3.57 + 3.57 imes 1.23 + 1.23 imes 1.23)+ 2.56 will be:
Q8. If a + b - c = 0, then hat is the value of(frac(b-c)^24bcfrac(c-a)^24cafrac(a+b)^24ab?)
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Q1. If the incomes of Ram & Shyam are in the ratio of 3 ∶ 4 & their expenditures in the ratio of 4 ∶ 5,find the ratio of their savings, given that Shyam saves a third of his income.

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Q2. The average of 6 observations is 12. If the 7th observation is included, the average is reduced by 1. What will be the 7th observation?
Q3. A sells his goods 20% cheaper than B and 20% dearer than C. How much percentage is C‟s goods cheaper / dearer than B.
Q4. A and B can bởi vì a piece of work in 18 days; B và C can vị it in 24 days, A and C can do it in 36 days. In how many days B alone can finish the work?
Q5. The average weight of 5 men is increased by 2 kilogam when one of the men whose weight is 60 kg is replaced by a new man. The weight of the new man is
Q6. A’s salary is 20% lower than B’s salary, which is 15% lower than C’s salary. By how much percent is C’s salary more than A’s salary?
Q7. The price of sugar increases by 20% due to lớn the festive season. By what percentage should a family reduce the consumption of sugar so that there is no change in the expenditure?
Q8. A Train travelling at a uniform speed clears a platform 200 m long in 10 seconds and passes a telegraph post in 5 seconds. The speed of the train is
Q9. A man travelled from a point A khổng lồ B at the rate of 25 Kmph and walked back at the rate of 4 Kmph. If the whole journey took 5 hrs 48 minutes, the distance between A & B is
Q10. A sells 2 TV sets at equal price, one at a loss of 15% & another at a profit of 15%. Find the loss/gain percentage in the overall transaction?