Answer:
Roy is 10 years old at present and Joan is 5 years old at present
Step-by-step explanation:
Let
x----> Roy's age
y----> Joan's age
we know that
x=2y ----> equation A
(x+3)+(y+3)=21 ----> equation B
substitute equation A in equation B
(2y+3)+(y+3)=21
solve for y
3y+6=21
3y=21-6
3y=15
y=5 years
Find the value of x
x=2y ----> x=2(5)=10 years
therefore
Roy is 10 years old at present
Joan is 5 years old at present
Answer:
+ 8/5
Step-by-step explanation:
Reciprocal is flip
Take the negative flip
- ( - 1 /(5/8))
+ 8/5
Answer:
Step-by-step explanation:
x²+y²=r²
r²=12
r=√12=2√3
1/3 * 7/9 kg = (1 * 7)/(3 * 9) kg = 7/27 kg
He used 7/27 kg of sugar.
Answer:
x = 39.1
Step-by-step explanation:
To find the mean, add up all the data points and then divide by the number of data points
(31.7+ 42.8+ 26.4+ x)/4 = 35
Multiply each side by 4
(31.7+ 42.8+ 26.4+ x)/4*4 = 35*4
(31.7+ 42.8+ 26.4+ x) = 140
Combine like terms
100.9+x = 140
Subtract 100.9 from each side
x = 140-100.9
x = 39.1
