answer:Alice wants x folded paper cranes. She folds half by herself, which means she folds (1/2)*x paper cranes. The remaining number of paper cranes is x - (1/2)*x = (1/2)*x. A friend folds a fifth of the remaining paper cranes for her, which means the friend folds (1/5)*((1/2)*x) = (1/10)*x paper cranes. The number of paper cranes Alice still needs to fold is the remaining number of paper cranes minus the number folded by her friend: (1/2)*x - (1/10)*x = (5/10)*x - (1/10)*x = (4/10)*x = (2/5)*x. We are given that Alice still needs to fold 400 paper cranes, so we can write: (2/5)*x = 400. Solving for x, we get: x = 1000. The value of x is 1000. 1000 The answer is: 1000

answer:Nina purchased three toys at 10 each, so she spent 3 * 10 = 30 on toys. She also purchased two packs of basketball cards at 5 each, so she spent 2 * 5 = 10 on basketball cards. Lastly, she purchased five shirts at 6 each, so she spent 5 * 6 = 30 on shirts. Therefore, the total amount spent by Nina is 30 + 10 + 30 = 70. 70 The answer is: 70

answer:To find the sum of two vectors, we simply add their corresponding components. So the sum of begin{pmatrix} -5 1 -4 end{pmatrix} and begin{pmatrix} 0 8 -4 end{pmatrix} is begin{pmatrix} -5 + 0 1 + 8 -4 + (-4) end{pmatrix} = begin{pmatrix} -5 9 -8 end{pmatrix}. Thus, the sum of the vectors is boxed{begin{pmatrix} -5 9 -8 end{pmatrix}}. The answer is: begin{pmatrix}-59-8end{pmatrix}

answer:If Jennifer will be 30 years old in ten years, that means she is currently 30 - 10 = 20 years old. If Jordana will be three times as old as Jennifer in ten years, that means Jordana will be 30 * 3 = 90 years old. Therefore, Jordana is currently 90 - 10 = 80 years old. 80 The answer is: 80