SAT OG 2道数学题 ,帮忙讲解一下哈～～ 在线等A measuring cup contains5/1 of orange juice.it is then filled to the 1 cup mark with a micture that contains equal amounts of orange,grapefruit,and pineapple juces.what fraction of the final mixture is orange juice?In the xy-plane,line L passes through the origins and is perpendicular to the line 4x+y=k,where k is a constant.if the two lines intersect at the point (t,t+1),what is the value of t?A -4/3B -5/4C 3/4D 5/4E
SAT OG 2道数学题 ,帮忙讲解一下哈～～ 在线等
A measuring cup contains5/1 of orange juice.it is then filled to the 1 cup mark with a micture that contains equal amounts of orange,grapefruit,and pineapple juces.what fraction of the final mixture is orange juice?
In the xy-plane,line L passes through the origins and is perpendicular to the line 4x+y=k,where k is a constant.if the two lines intersect at the point (t,t+1),what is the value of t?
A -4/3
B -5/4
C 3/4
D 5/4
E 4/3
第一道题看不懂 第二道是xy平面内，直线L经过原点，且与垂直于直线4x+y=k.若直线L与直线4x+y=k有交点（t,t+1),求t? t=-4/3 A
你要把分给我撒 谢谢
第一题：
一个杯子里面有五分之一的橙子,这个杯子的橙子被一个由同等量的 橙子,葡萄汁,和菠萝果汁混合溶液稀释到一整杯.问最终溶液中橙子的分数?
用了五分之四的溶液稀释,这五分之四的溶液有同等量的三种果汁,那么之中的橙子量就是 (4/5) x (1/3) = 4/15,这十五分之四杯橙子,加上原来在杯子里面五分之一的橙子,答案就是共 7/15杯橙子.
第二题：
在XY平面上,直线L穿过原点并与直线 4x + y = k 垂直,k是常数.问如果两条直线相交于点 (t,t + 1) ,那么t的值是多少?
从给出的等式化出 y = -4x + k,那么坡度就是 -4,学过的就知道当两线垂直,坡度为倒数,那直线L的坡度为 - 1/4.之后代入t,t + 1等得出两个式子,y = -4x + k,y = (-1/4)x + (k+3)/4,且 t = (k-1)/5.代入即可.