In a class of 25 students , 12 have taken in mathematics , 8 have taken mathematics but not biology . Find
2 answers:
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Answer: 1:1
Step-by-step explanation:
Let r be the radius and h be the height of a cylinder.
Formula: Curved surface area of cylinder =
Now, if radius of a cylinder is doubled and its height is halved, then new radius will be R= 2r and new height will be
Now, new surface area =
Ratio of curved surface areas :
Hence, the ratios of their surface areas = 1:1 .
Answer:
Step-by-step explanation:
1). 10 =
10(7 + x) = 1 + 7x
70 + 10x = 7x + 1
10x - 7x = 1 - 70
3x = -69
x = -23
2). 0.2 =
0.2(12 + x) = 6 + 2x
2.4 + 0.2x = 6 + 2x
2.4 - 6 = 2x - 0.2x
1.8x = -3.6
x = -2
3). 0.8 =
0.8(x + 0.5) = x
0.8x + 0.4 = x
x - 0.8x = 0.4
0.2x = 0.4
x = 2
4). 3.5 =
3.5(0.5 - x) = 4 + 2x
1.75 - 3.5x = 4 + 2x
-3.5x - 2x = 4 - 1.75
-5.5x = 2.25
x = -
x = -