Question

Por favor me ajude! Atividade de matemática abrem o "PDF"

0155b9843c85f5b84708ce8b32fe0fad.pdf

Answer 1

Explicação passo-a-passo:

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1)

200 ----- 100%

25 ------- x

$\dfrac{200}{25} =\dfrac{100}{x}\\\\8=\dfrac{100}{x}\\\\x=\dfrac{100}{8}\\\\\boxed{\boxed{x=\text{12,5\%} }}$

Resposta A

2)

30-----15%

x ------- 100%

$\dfrac{30}{x} =\dfrac{15}{100}\\\\15x=30.100\\\\x= \dfrac{3000}{15}\\\\\boxed{\boxed{x=200}}$

Resposta B

3)

30 alunos ------- 100%

   x       ------------- 40%

$\dfrac{30}{x} =\dfrac{100}{40} \\\\100x=30.40\\\\100x=1200\\\\x=\dfrac{1200}{100}\\\\\boxed{\boxed{x=12\ meninas}}$

Resposta B

4)

$\dfrac{2}{5} \\\\\text{Multiplicando o numerador e o denominador por 20:}\\\\\dfrac{2.20}{5.20}\\\\\dfrac{40}{100}\\\\\boxed{\boxed{40\%}}$

Resposta D

5)Júlia acertou 75% das questões.

$\text{Mariane acertou }\dfrac{4}{5}\\\\\text{Multiplicando o numerador e o denominador por 20: }\\\\\dfrac{4.20}{5.20}=\dfrac{80}{100} =\boxed{\boxed{80\%}}$

Logo, Mariane acertou mais questões.

Resposta B

6)

400 reais ------ 100%

x         ----------- 100-12=88%

$\dfrac{400}{x} =\dfrac{100}{88} \\\\100x=400.88\\\\x=\frac{400.88}{100}\\\\x=4.88\\\\\boxed{\boxed{x=352\ \text{reais}}}$

Resposta D

7)

145 reais ------ 100%

 x    -------------- 100-15=85%

$\dfrac{145}{x} =\dfrac{100}{85}\\\\100x=145.85\\\\100x=12325\\\\x=\dfrac{12325}{100}\\\\\boxed{\boxed{x=\text{123,25 reais} }}$

Resposta B