Answer:
Will's age = 9 years
Bill's age = 11years
Step-by-step explanation:
Let will age = x
Bill = x +2 since he is 2 years older
x(x+2) = 5( x +x+2) - 1
Opening brackets
x² + 2x = 5(2x + 2) - 1
x² + 2x = 10x + 10 - 1
x² + 2x = 10x + 9
Collect like terms
x² + 2x - 10x - 9 = 0
x² - 8x - 9 = 0
Solve quadratically using factorisation method by finding two factors of +9 that can add up to give -8, the coefficient of x.
The factors are -9 and +1
x² + x - 9x - 9 = 0
x(x + 1) -9( x +1)
x+1) (x -9) =0
x + 1 = 0 or x -9 =0
x = -1 or 9
Age can not be negative
Therefore,
Will's age = 9 years
Bill's age = x+2 = 9+2 = 11years
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Answer:
r =29.82
Step-by-step explanation:
r/7.1 = 4.2
Multiply each side by 7.1
r/7.1 *7.1 = 4.2*7.1
r =29.82
15÷1/3= 45 so the students made 45 clay plates
Answer:
A. Cylinder + cone
<u>Volume is the sum of volumes:</u>
- V = Vcon + Vcyl = 1/3πr²h₁ + πr²h₂
- V = 1/3π*9²*12 + π*9²*120 = 31554.2 cm³
<u>Surface area of cone:</u>
- A = A=πr(r+√(h₁²+r²)) = π*9(9 + √(9²+12²)) = 678.6 cm²
<u>Surface area of cylinder minus bases:</u>
- A = 2πrh₂ = 2π*9*120 = 6785.8 cm²
<u>Total surface area:</u>
- 678.6 + 6785.8 = 7464.4 cm²
-------------------------------------------------
B. Cube+ pyramid
<u>Volume:</u>
- V = a³ + (1/3)a²h = a³ + (1/3)a²√(l²-(a/2)²)
- V = 8³ + (1/3)8²√(10²-4²) = 707.5 cm³
<u>Surface area of pyramid:</u>
- A = a² + 2al = 8² + 2*8*10 = 224 cm²
<u>Surface area of cube minus bases:</u>
- A = 4a² = 4(8²) = 256 cm²
<u>Total surface area:</u>
Answer:
It represents the millions place, so in this case 3,000,000
Step-by-step explanation:
